Definition of "ovoid"

That was the way my mind lurched and stumbled, among the sharp r's and t's, sliding over the ovoid vowels as if on pebbles.

1985, Margaret Atwood, “Soul Scrolls”, in The Handmaid’s Tale, Toronto, Ont.: McClelland and Stewart, page 164

And then they were looking at him, Mrs. Ansen's ovoid black eyes behind bifocals attached to a chain, Baffi's beautiful hazel eyes bright with the promise of fun and friendly competition, and what else could Patrick say, other than no, he didn't have anything else going on this afternoon, and yeah, come to think of it, Cokes and leftover pizza would be nice.

2016, Christopher Kelly, The Pink Bus, Mapple Shade, New Jersey: Lethe Press, page 43