📖 Glossary

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Quick Cheat Sheet

Term	Example	Meaning
Symbol	EURUSD, XAUUSD	Trading instrument identifier.
Lot	1.00 → usually 100,000 units	Standard trade size.
Volume	0.10, 2.50	Lots to trade (can be fractional).
SL	1.09500	Stop Loss — protective exit level.
TP	1.10500	Take Profit — target exit level.
Ticket	12345678	Unique order/position/deal ID (uint64 in most RPCs).
Digits	5	Quote precision; e.g., 1.23456 for 5 digits.
Point	0.00001 (EURUSD)	Smallest price step for the symbol.
Pip	0.0001 (most FX majors)	Conventional 1 «pip» (may differ from point).
Margin	100.00	Funds locked for open exposure.
Equity	1000.00	Balance ± floating P/L.
Free Margin	900.00	Equity − Margin.
Leverage	1:500	Borrowed funds ratio.
Market Watch	selected symbols in the terminal	The watchlist used by selected_only=True in some RPCs.
DOM/Book	Market Depth	Level‑2 price ladder; see Market Book methods.
Enum	BMT5_ENUM_*, MRPC_ENUM_*	Strongly‑typed constants — no «magic numbers».
Retcode	10009, TRADE_RETCODE_DONE	Trade server return code (see error mapping).
Deadline	now() + 3s	Per‑call absolute deadline → turned into gRPC timeout.
Cancellation	asyncio.Event()	Cooperative stop for retry/stream wrappers.
Stream	on_trade(), on_symbol_tick()	Long‑lived server push (events until cancelled).

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📊 Order & Position Lifecycle

   ┌─────────────┐
   │  New Order  │  (market or pending)
   └──────┬──────┘
          │
          │ executed → DEAL_ADD (may create/affect POSITION)
          ▼
   ┌─────────────┐
   │   Opened    │  (POSITION with floating P/L)
   └───┬─────┬───┘
      SL     TP
      │      │
      ▼      ▼
   ┌─────────────┐      pending order can be
   │   Closed    │ ◄─── deleted/cancelled before fill
   └─────────────┘

MT5 note: in hedging mode multiple positions per symbol can coexist; in netting — one net position per symbol.

🧑‍💻 Account Terms

• Login / Server — broker account ID and server name.

• Balance / Equity / Margin / Free — see cheat sheet; numbers come from:

• Account Information Overview

• Currency Digits — use ACCOUNT_CURRENCY_DIGITS (integer) to format money correctly.

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📈 Market Info Terms

• Symbol Inventory — size & presence checks:

• symbols_total.md

• symbol_exist.md
• symbol_name.md

• symbol_select.md

• Properties — double/int/string getters & bulk params:

• symbol_info_double.md

• symbol_info_integer.md
• symbol_info_string.md

• symbol_params_many.md

• Quotes & Sessions — tick snapshot and trading/quote sessions:

• symbol_info_tick.md

• symbol_info_session_quote.md

• symbol_info_session_trade.md

• Margin model — per‑order type margin rate & calc helpers:

• symbol_info_margin_rate.md

• order_calc_margin.md

• tick_value_with_size.md

• Market Book (DOM) — subscribe/read/release:

• market_book_add.md

• market_book_get.md
• market_book_release.md

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📦 Orders & History Terms

• Live snapshot

• opened_orders.md

• opened_orders_tickets.md (IDs‑only)

• History

• order_history.md (orders + deals)

• positions_history.md

• Count

• positions_total.md

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🔌 RPC & Streaming Terms

• Unary RPC — one request → one reply; returns *.Data payload already unwrapped.

• Streaming RPC — server pushes events until you cancel:

• on_symbol_tick.md

• on_trade.md
• on_trade_transaction.md
• on_position_profit.md

• on_positions_and_pending_orders_tickets.md

• Deadline & Cancellation — pass deadline (to set timeout) and cancellation_event (to stop cleanly).

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🛡️ Errors & Codes

• gRPC transport — timeouts, unavailables; wrappers auto‑retry via execute_with_reconnect(...).
• Trade retcodes — see numeric+string mapping in package/MetaRpcMT5/mrpc_mt5_error_pb2.py and docs for order_* / on_trade_transaction.
• Validation — prefer enums over raw ints/strings to avoid typos.

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✅ One‑page Summary

• Account — who you are & your limits.
• Market Info — what you can trade and how it’s specified.
• Orders/History — what’s live & what happened before.
• RPC — unary vs streaming, with deadlines & cancellation.
• Errors — retcodes & transport issues, surfaced cleanly by the SDK.