トレード用語をやさしく解説
初心者トレーダーが必ず知っておくべき 100 の必須用語。専門用語なし、実例つき、そしてそれぞれの用語で初心者が最もやりがちなミスまで。
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1% Rule
🛡️ Risk Management- どういう意味か
- A simple risk rule: never risk more than 1% of your total account on a single trade. It keeps any one loss from doing real damage.
- 例
- On a $10,000 account, 1% is $100. If your stop is $5 below entry, you can buy 20 shares. Even 10 losing trades in a row leave you with $9,000 -- survivable.
- ⚠ 初心者がよくやるミス
- Beginners confuse "1% risk" with "1% of the position." Risking 1% means the loss if your stop is hit equals 1% of the account, not that the position size is 1% of the account.
- 関連用語
Ask
📘 Basics- どういう意味か
- The lowest price a seller is currently willing to accept. It is the price you pay if you buy right now.
- 例
- If AAPL shows an ask of $150.05, a buyer using a market order to buy 1 share pays $150.05 per share.
- ⚠ 初心者がよくやるミス
- Beginners assume the price on the screen is what they pay, then are surprised the fill comes in at the ask, which is always slightly higher than the mid price they were watching.
- 関連用語
Assets Under Management
📘 Basics- どういう意味か
- The total market value of all the assets that an investment fund (like an ETF or mutual fund) manages. Larger AUM generally means the fund is more stable, popular, and liquid.
- 例
- VOO has over $1 trillion in AUM, making it one of the largest ETFs in the world. A tiny ETF with only $10 million in AUM may have liquidity issues.
- ⚠ 初心者がよくやるミス
- Beginners think "bigger AUM = always better." While very small AUM can indicate liquidity risk, huge AUM is not always an advantage. For niche strategies, smaller funds can be more flexible.
- 関連用語
Backtesting
🧠 Psychology- どういう意味か
- Running a strategy over historical data to see how it would have performed, before risking real money on it. It is the lab test for a trading idea.
- 例
- You test "buy the 50/200 SMA crossover on AAPL, 2010-2024" and find 28 trades, a 46% win rate, and +0.4R per trade. The strategy is marginally profitable -- worth paper-trading next.
- ⚠ 初心者がよくやるミス
- Beginners over-tune settings until the backtest looks perfect, then lose live. A perfectly fit backtest is overfit -- it predicts the past, not the future. Test out-of-sample data too.
- 関連用語
Bear Market
📘 Basics- どういう意味か
- A market where prices are falling, usually defined as a drop of 20% or more from recent highs. Pessimism and selling dominate buying.
- 例
- In 2022 the S&P 500 fell from about 4,796 to 3,636, a 24% decline, meeting the common definition of a bear market.
- ⚠ 初心者がよくやるミス
- Beginners try to "buy the dip" in a bear market the same way they would in a bull market, catching falling knives all the way down because dips keep making new lows.
- 関連用語
- Related Guides
- Crypto Market Cycles →Fear and Greed Index →Bitcoin →
- Related Comparisons
- ⚖ Bull Market vs Bear Market: Trend Direction →
Bid
📘 Basics- どういう意味か
- The highest price someone is currently offering to pay for an asset. It is the price you get if you sell right now.
- 例
- If AAPL shows a bid of $150.00, a seller using a market order to sell 1 share receives $150.00 per share.
- ⚠ 初心者がよくやるミス
- Beginners stare at the last traded price and assume that is what they will get, but the bid -- the live offer to buy -- is the real cash-out price the instant you sell.
- 関連用語
- どういう意味か
- The difference between the highest price a buyer is willing to pay (bid) for an asset and the lowest price a seller is willing to accept (ask). Tighter spreads mean lower trading costs.
- 例
- If an ETF has a bid price of $100 and an ask price of $100.05, the bid-ask spread is $0.05. On a 100-share trade, your total trading cost from the spread is $5.
- ⚠ 初心者がよくやるミス
- Beginners ignore bid-ask spreads, especially on low-volume or niche ETFs. Wide spreads can eat into your returns every time you buy or sell, even if the ETF itself performs well.
- 関連用語
Blockchain
📘 Basics- どういう意味か
- A decentralized, distributed digital ledger that records transactions across many computers. Each "block" contains transaction data, and blocks are linked chronologically in a "chain". Blockchains are the technology underneath most cryptocurrencies.
- 例
- Bitcoin's blockchain records every Bitcoin transaction since 2009, and is maintained by a global network of computers rather than a central authority.
- ⚠ 初心者がよくやるミス
- Beginners think "Bitcoin = blockchain". Blockchain is the technology; Bitcoin is the first application of that technology. There are many other blockchains beyond Bitcoin.
- 関連用語
- Related Guides
- Bitcoin →Ethereum →On-Chain Analysis →
- Related Comparisons
- ⚖ Bitcoin vs Ethereum: What's the Difference? →⚖ Proof of Work vs Proof of Stake: Consensus Compared →
- Related Answers
- 💡 What is Bitcoin? →💡 What is Ethereum? →
Bollinger Bands
📊 Technical Analysis- どういう意味か
- Two lines plotted two standard deviations above and below a 20-period moving average. They widen when volatility rises and squeeze tight when it falls.
- 例
- Price normally stays within the bands. When it closes outside the upper band at $120, with the middle band at $110, it is stretching -- a pullback or stronger volatility may follow.
- ⚠ 初心者がよくやるミス
- Beginners short the upper band and buy the lower band blindly. Touching the band is not a signal; the band can ride along with price for days in a strong trend.
- 関連用語
Bracket Order
📋 Order Types- どういう意味か
- A single order that, once filled, automatically attaches a take-profit and a stop-loss to it. It defines your risk and target before you enter.
- 例
- You enter a bracket buy of 100 shares at $100. The bracket sets a take-profit at $110 and a stop at $95 -- filling either one cancels the other automatically.
- ⚠ 初心者がよくやるミス
- Beginners trade without brackets and try to manage exits manually under stress, which is exactly when they freeze. Pre-defined brackets remove the in-the-moment decision.
- 関連用語
Break-even
🎯 Options- どういう意味か
- The underlying price at which an option trade results in zero profit at expiration. For call options, break-even is strike price + premium per share. For put options, break-even is strike price - premium per share. The underlying must move past the break-even point at expiration for the trade to be profitable.
- 例
- You buy a call with a $500 strike and $3 premium. The break-even price is $503. If SPY closes at $503 at expiration, you make $0 profit. If it closes above $503, you profit; if it closes below $503, you lose money (up to the full $300 premium if SPY is at or below $500).
- ⚠ 初心者がよくやるミス
- Beginners think they only need the underlying to move in their direction to profit, but they forget to account for the premium paid. You need the underlying to move far enough to cover the premium before you can start making money.
- 関連用語
Breakout
📊 Technical Analysis- どういう意味か
- When price moves clearly beyond a support or resistance level, often with rising volume. It hints that a new move in the breakout direction has started.
- 例
- A stock has rejected $100 five times. On the sixth attempt it closes at $102 on twice the normal volume -- that breakout suggests $100 is now support and $110+ is in play.
- ⚠ 初心者がよくやるミス
- Beginners chase the breakout candle at the very top, then watch price reverse in a "fakeout." Waiting for a retest of the broken level gives a safer entry and a clear stop.
- 関連用語
Broker
🏗️ Market Structure- どういう意味か
- The company that holds your account, takes your orders, and routes them to exchanges. You trade through a broker, not directly with other traders.
- 例
- You open an account with a broker like Interactive Brokers, deposit $5,000, and place orders through their platform. They route each order to an exchange and report fills back to you.
- ⚠ 初心者がよくやるミス
- Beginners pick a broker based on ads, then discover slow execution, wide spreads, or withdrawal issues. Always check regulation, fees, and execution quality before depositing.
- 関連用語
Bull Market
📘 Basics- どういう意味か
- A market where prices are rising or expected to rise over a sustained period. Traders are optimistic and buying dominates selling.
- 例
- From March 2009 to early 2020, the S&P 500 rose from about 676 to 3,386 -- a long bull market that multiplied invested money roughly five times.
- ⚠ 初心者がよくやるミス
- Beginners assume a bull market means "stocks only go up" and buy with no stop-loss, then are shocked when a normal 10-20% pullback within a bull market hits them.
- 関連用語
- Related Guides
- Crypto Market Cycles →Fear and Greed Index →Bitcoin →
- Related Comparisons
- ⚖ Bull Market vs Bear Market: Trend Direction →
Call Option
🎯 Options- どういう意味か
- A contract that gives you the right (but not the obligation) to buy 100 shares of an underlying asset at a fixed price (the strike price) by a specific date (the expiration date). You buy a call when you expect the underlying price to rise above the strike price plus the premium you paid.
- 例
- You buy 1 SPY call option with a $500 strike price and $3 per share premium ($300 total cost, since 1 contract = 100 shares). If SPY rises to $510 at expiration, you make $10 per share × 100 shares = $1,000, minus the $300 premium, for a net profit of $700.
- ⚠ 初心者がよくやるミス
- Beginners forget that most out-of-the-money call options expire worthless if the underlying price does not rise above the strike price. You can lose 100% of the premium you paid if the trade does not work out before expiration.
- 関連用語
Candlestick
📊 Technical Analysis- どういう意味か
- A bar that shows the open, high, low, and close price for a period. The body is colored (green/red) by whether close was above or below open.
- 例
- A green 1-hour candle with open $100, close $105, low $99, high $106 has a $5 green body and thin wicks above and below -- price rose over the hour.
- ⚠ 初心者がよくやるミス
- Beginners read one candle in isolation and call it a signal. A single candle means almost nothing; what matters is where it forms relative to the surrounding context.
- 関連用語
Chart Pattern
📊 Technical Analysis- どういう意味か
- A recognizable shape formed by price over time that, based on history, hints at what price may do next. Examples include head and shoulders, flags, and triangles.
- 例
- A head and shoulders pattern at the top of a long rally -- two smaller peaks around a taller middle peak -- is a classic hint that the up trend may be ending.
- ⚠ 初心者がよくやるミス
- Beginners see patterns everywhere, even in random noise. If you have to squint and redraw lines to make it fit, it is not a pattern -- it is wishful thinking.
- 関連用語
Circuit Breaker
🏗️ Market Structure- どういう意味か
- A market-wide rule that pauses all trading if a major index falls a set amount in a day, to let traders calm down. Different levels trigger longer pauses.
- 例
- In the US, if the S&P 500 drops 7% before 3:25 p.m., trading halts for 15 minutes (Level 1). A 13% drop triggers another 15-minute halt; a 20% drop ends trading for the day.
- ⚠ 初心者がよくやるミス
- Beginners expect their stop-loss to protect them during a circuit-breaker halt. It cannot -- once trading resumes, price may gap straight through your stop to a much worse fill.
- 関連用語
Correlation
🛡️ Risk Management- どういう意味か
- How much two assets move together, from -1 (opposite) to +1 (identical). 0 means no relationship. It decides whether diversification is real.
- 例
- Two tech stocks might have +0.85 correlation -- they usually rise and fall together, so holding both barely reduces risk. A tech stock and gold might be near 0, giving real diversification.
- ⚠ 初心者がよくやるミス
- Beginners assume "different tickers = diversified." In a crash, correlations jump toward 1 and everything falls together; true diversification needs assets that are uncorrelated in bad times.
- 関連用語
Day Order
📋 Order Types- どういう意味か
- An order that is automatically canceled at the end of the trading day if it has not filled. Most orders are day orders by default.
- 例
- A day buy limit at $100 on AAPL placed at 10:00 a.m. is canceled at 4:00 p.m. if AAPL never reached $100 during the session.
- ⚠ 初心者がよくやるミス
- Beginners assume their unfilled limit order will keep working tomorrow. By default it dies at the close; you must re-place it each day or use a GTC order.
- 関連用語