Term	Definition
Trigram	A 3-character sequence extracted from text. For example, “function” produces trigrams: “fun”, “unc”, “nct”, “cti”, “tio”, “ion”. Used as an index key to quickly find candidate files containing a search term.
Roaring Bitmap	A compressed data structure for storing sets of integers efficiently. Used to store which document IDs contain each trigram. Supports fast set operations (intersection, union) for combining multiple trigram lookups.
Memory-mapped file	A file access technique where the OS maps file contents directly into virtual memory. Allows reading files without explicit I/O calls—the OS handles paging data in/out as needed. Reduces memory usage for large codebases.
AST (Abstract Syntax Tree)	A tree representation of source code structure. Used via tree-sitter to identify symbol definitions (functions, classes, methods, types, etc.) for smarter ranking.
Symbol	A named code element like a function, class, method, or variable. Extracted using tree-sitter parsing. Symbol matches are boosted 3x in search results.
TF-IDF	Term Frequency–Inverse Document Frequency. A text vectorization technique that weights words by how important they are to a document relative to the corpus. Used for semantic search embeddings.
Embedding	A vector (array of numbers) representing text in a high-dimensional space where similar meanings are close together. Enables “find similar code” queries.
Import graph	Which indexed file imports which, resolved from import statements (Rust, Python, JavaScript/TypeScript). Drives the dependency ranking boost, the deps popover and the dependency explorer (/graph.html, /api/graph/*).
Containment edge	A Rust mod foo; declaration (or a pub use foo::X re-export of a child module): an edge from a parent module to its own child. It describes structure rather than a dependency, so the explorer hides it by default.
gRPC	Google Remote Procedure Call. A high-performance protocol for server communication. Used for streaming search results to IDE clients.