a hanging protrusion that catches the eye: a blossom-shaped tassel of threads worn at a garment's corner, or by extension a lock of hair
The word belongs to a root cluster (ציץ) whose unifying idea is something that bursts forth into visibility from a surface: a blossom from a branch, a gleam from metal, a face appearing at a window. Applied to textiles, it describes the blossom-shaped bundle of threads hanging from the corner of a garment: decorative, status-marking, and in Israel's law charged with deep symbolic weight. Applied to the body, the same logic yields a lock or tuft of hair: something that sprouts and hangs from the head.
The two concrete uses are not unrelated accidents. Both are things that protrude, dangle, and draw the eye: the same physical grammar in different materials. Most modern lexicographers (HALOT, BDB, DCH) treat them as two uses of one polysemous noun rather than two homonyms. The botanical parent noun (ציץ, H6731) supports this reading: blossoms, tassels, golden ornaments, and locks of hair all occupy the same conceptual space of "a hanging, visible protrusion."
In its dominant use (the four garment-corner tassels commanded in Numbers 15:38–39), the word describes what ANE iconography confirms was the insignia of the powerful: elaborately fringed hems worn by kings, gods, and warriors signified identity, authority, and status. Israel's law placed this aristocratic badge on every member of the nation, with a costly blue-violet cord (techelet) making the priestly and royal associations explicit. The tassel was simultaneously a practical mnemonic ("look at it and remember all the commandments") and a material enactment of the claim that Israel was a kingdom of priests.