A byte-order mark — an invisible sign at the start of a file saying how it is encoded. Small, unseen, and capable of breaking everything downstream.

Short form of document. A written thing kept as a reference.

A work as written before it is published. Literally hand-written — the form a thing takes while still the author's.

Running across more than one line. Of a thing too long to be held in a single row.

Short form of specification — a statement of exactly what a thing must be. A spec is a contract before it is a plan.