Shared language for advanced-era D&D

These terms show up constantly in advanced-era keys and Dragonsfoot threads. If a definition fights your house table, write the house call once and move on.

THAC0

To Hit Armor Class 0—attack math from advanced-era tables.

Segment

Initiative slices used in some advanced combat procedures.

Saving throw matrix

Class-and-level based defenses against spells and hazards.

Non-weapon proficiency

Optional skill-like training outside combat.

Module code

Catalog identifiers for published adventures.

Henchmen

Loyal retainers who expand logistics and drama.

Demihuman level limits

Edition-specific caps often house-ruled away.

Alignment languages

Setting flavor some tables keep, many drop.

More craft in Guides; outbound doors in Resources.