Triangle Terminology for Geometry
Triangles are at least a third of geometry (tri = three . . . a little geometry humor). But, seriously, the sides and angles of triangles may have all sorts of relationships to each other, and the following list shows the abbreviations that indicate these relationships:

SSS: Sidesideside congruency

SAS: Sideangleside congruency

ASA: Anglesideangle congruency

AAS: Angleangleside congruency

HL(R): Hypotenuseleg(right angle) congruency

AA: Angleangle similarity

SSS~: Sidesideside similarity

SAS~: Sideangleside similarity

CPCTC: Corresponding parts of congruent triangles are congruent

CSSTP: Corresponding sides of similar triangles are proportional