plural: chalazae or chalazas
1. (Biology) One of two spiral bands of tissues inside an egg that suspend the yolk in the center of the white.
2. (Botany) The region of an ovule that is opposite the micropyle, where the integuments and nucellus are joined.
All those other botany words are kindly defined here. (After fertilization, the ovule becomes a seed.)
Etymology: Greek khalaza, hard lump, hailstone
This week's word is brought to you by my attempts to up my deviled egg-making game. The internet has many suggestions for getting the yolks centered before the eggs are cooked; some involve rotating or twirling the eggs to twist up the chalazae. I didn't have time to do the easy option (set the egg box on its side overnight), or the patience to do any of the other options properly, but the eggs turned out sufficiently centered.
I also learned that adding baking soda to the water when boiling the eggs makes them easier to peel (so does using older eggs, but I didn't have time to wait for that either).