Glossary

Term	Meaning
COM	Canonical Object Model — in-memory contract after parse
Contract	Transformation Contract document (YAML/JSON)
dtcsVersion	Spec version this document targets. Prefer "3.0.0"; "2.0.0" / "1.0.0" / "1.0.0-draft" still accepted
Diagnostic	Structured finding with severity, code, and stage
Engine capability profile	Declared engine features used by match
Execution plan	Compiled step list for a runtime backend
Flow	Lineage information-flow kind (preserved, derived, filtered, …)
Function	Named COM function, often backed by a dtcs: registry entry
Lineage mapping	Declares which inputs contribute to an output
Missing	Distinct from null; JSON {"$dtcs":"missing"}
Invalid	Distinct from null; JSON {"$dtcs":"invalid"}
Operation	Lineage mapping operation id (default dtcs:derive)
Plan	Transformation plan IR after lowering
Reference runtime	In-memory executor in this repo (not a warehouse)
Registry	Catalog of standard/vendor identifiers
Rule	Constraint evaluated at a phase (pre/execution/post)
Semantic action	Declared transform (dtcs:lowercase, dtcs:project, …)
Portable Relational	Spec 2.0 / 3.0 profile family for joins, aggs, windows, datetime, and complex access
Portable plan	Serializable transform-plan IR (dtcs.transform-plan/2; /1 still migrates) for engine interchange
SPEC	Normative DTCS document (SPEC.md, currently draft 3.0.0)

See also versioning.md and SPEC Chapter 1 §9 / Chapter 2.