tinycast/docs/features/dictionary.md

Dictionary

Define Word is a launcher command and a fallback. The command opens the dictionary screen (.dictionary) empty; the fallback opens it on whatever was typed. The search field stays the term, so a different word is one edit away. Everything is read from the dictionaries enabled in Dictionary.app — no network, no bundled word list.

Invariants

• The command gates the fallback, never the reverse. Define Word has no feature pane, so Settings › Commands is its switch: while the command is hidden there — itself or the whole Commands category — FallbackCoordinator offers no Define Word fallback and Settings › Fallbacks does not list it. While it is visible, the fallback's own checkbox hides just the fallback, leaving the command searchable.
• The page comes from an undocumented call, resolved at run time. The public DCSCopyTextDefinition returns one unbroken line, so DictionaryService asks for the record's XHTML through DCSGetActiveDictionaries, DCSCopyRecordsForSearchString and DCSRecordCopyData — what Dictionary.app itself reads. They are found with dlsym, never linked: a macOS that drops one loses the layout and falls back to the public plain text, rather than failing to launch.
• The span classes are the only structure, and DictionaryMarkup is the only reader of them. hg is the headword, posg the part of speech, se2 a numbered sense, msDict its definition or a t_subsense bullet, note an aside, x_xoLblBlk a section label (ORIGIN, PHRASES). Unknown markup reads as plain text in the nearest block, so a format change degrades rather than drops words. dictionary-test holds a real record as its fixture.
• Lookups run off the main actor. A long entry (run, take) is a few hundred blocks, so DictionarySession debounces the query and looks it up detached, the way FileSearchSession does. The previous page stays up until the next resolves, and ↵ and ⌘K act on that page — what is shown is what is copied — so neither the page nor the footer flickers while typing.

Actions

Key	Does
↵	Copy Definition — the whole entry, one line per block, then the palette closes
⌘↵	Open in Dictionary — dict://<term>, for every other enabled dictionary

The first enabled dictionary that knows the term answers, in Dictionary.app's own order. A term none of them knows reads "No definition found".