the ankle bones collectively, 1670s, Modern Latin, from Greek tarsos "ankle, sole of the foot, rim of the eyelid," originally "flat surface, especially for drying," from PIE root *ters- "to dry." The connecting notion is the bones of the "flat" of the foot (Greek tarsos podos).
suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit tarsayati "dries up;" Avestan tarshu- "dry, solid;" Greek teresesthai "to become or be dry," tersainein "to make dry;" Latin torrere "dry up, parch," terra "earth, land;" Gothic þaursus "dry, barren," Old High German thurri, German dürr, Old English þyrre "dry;" Old English þurstig "thirsty."
