Webster’s Revised Unabridged Dictionary · 1913
Curdle
Cur′dle (k?r′d'l), v. i. [From Curd.] [Sometimes written crudle and cruddle.] 1. To change into curd; to coagulate; as, rennet causes milk to curdle. Thomson.
2. To thicken; to congeal.
Then Mary could feel her heart's blood curdle cold. Southey.
Cur′dle, v. t. [imp. & p. p. Curdled (-d'ld); p. pr. & vb. n. Curdling (-dl?ng).] 1. To change into curd; to cause to coagulate. "To curdle whites of eggs" Boyle.
2. To congeal or thicken.
My chill blood is curdled in my veins. Dryden.