late 14c., "metrical foot consisting of two long syllables," from Old French spondee, from Latin spondeus, from Greek spondeios (pous), the name of the meter originally used in chants accompanying libations, from sponde "solemn libation," related to spendein "make a drink offering," from PIE root *spend- "to make an offering, perform a rite," hence "to engage oneself by a ritual act" (cf. Latin spondere "to engage oneself, promise," Hittite shipantahhi "I pour out a libation, I sacrifice").
spondee spon·dee (spŏn'dē')
n.
A word or metrical foot having two equally stressed syllables, used in testing speech and hearing.