caesura (n.)

"a pause about the middle of a metrical line" (often coinciding with a pause in sense), 1550s, from Latin caesura, "metrical pause," literally "a cutting," from past participle stem of caedere "to cut down" (from PIE root *kae-id- "to strike"). In classical use, "the division of a metrical foot between two words, a break within a foot caused by the end of a word," as opposed to a diaeresis, a pause between feet.