lives
The legend of the cat's nine lives lives on.
The first lives is the plural of the noun life, pronounced /laɪvz/ with the long 'eye' vowel; the second is the third-person singular of the verb live, pronounced /lɪvz/ with the short 'i'. Unlike 'live' itself, where adjective and verb share a single base form, this pair exists only after inflection: the plural -s of the noun and the agreement -s of the verb land on the same five letters, and the noun's f-to-v voicing (life, lives) is what lets the plural catch up with the verb's spelling. Because the subject is 'the legend' rather than 'the lives', the reader must re-parse the identical string from object-of-preposition to main verb in a single step, and that switch is exactly where the vowel flips.
Meanings
Plural of life: the separate spans of existence belonging to different beings, or the courses and ways of living that people lead.
- The rescue crew saved four lives that night.
- They led quiet lives on the edge of the moor.
Third-person singular present of live: is alive, dwells in a place, or continues to exist or be remembered.
- She lives two streets from the harbor.
- His name still lives in the town's songs.
Word origin
Both words descend from Old English and from the same Proto-Germanic stem: the noun from Old English līf ('life, existence'), the verb from libban and lifian ('to be alive, to dwell'). They are traced to a Proto-Indo-European root meaning 'to remain, to persist', so to live was originally to stay on, and a life was the span one stayed. The noun's plural līfas already had a voiced v-sound between the vowels, which is why modern English writes lives rather than lifes.
Fun fact
The f-to-v plural is not quite fixed: the paintings are usually 'still lifes', not 'still lives', because a freshly coined compound noun takes the regular -s plural and keeps its f, the same way Toronto's hockey team is the Maple Leafs rather than the Maple Leaves. That makes 'still lives' a ready-made trap: it can only be read as the verb, as in 'the painter still lives in the village'.