Concept: gender system

Definition

A gender system (= a system of gender markers) is a system of non-numerative nomifiers which includes no more than 20 nomifiers.

Croft's comparative concept
gender/class (SEM):

gender/class (SEM) = a semantic category that is expressed as an indexation feature, and covers both distinctions based primarily on sex and animacy (‘gender’) and distinctions based on animacy, sex, and various semantic properties of inanimate – or at least nonhuman – objects. (Section 4.4.2)

Wikipedia
grammatical gender
SIL Glossary
grammatical gender