tpi en · NOUN Meanings (abbreviation, alt-of, initialism, plural, plural-only) Initialism of teeth per inch — a measure used on saw blades alt of teeth per inc (abbreviation, alt-of, initialism, plural, plural-only) Initialism of tracks per inch — a measure of disk capacity alt of tracks per inc (abbreviation, alt-of, initialism, plural, plural-only) Initialism of threads per inch — a measure of the density of threads in screwable parts (e.g. bottom brackets). alt of threads per inc