to become compressed into a shape reminiscent of a concertina / to be drawn closer and farther apart repeatedly, or up and down, as if situated on a working concertina's folds

Either concept, the inverse of the other, of a conceptual pair.

(transitive, obsolete) To acquire, to procure. / (transitive, now rare) To reconcile (discordant theories, demands etc.); to make compatible, bring together.

Not dilute; having a high concentration. / Intense; directed towards a specific location.

simple past tense and past participle of concentrate

The act of conceiving. / The state of being conceived; the beginning. / The fertilization of an ovum by a sperm to form a zygote. / The start of pregnancy.

the study of molluscs and their shells / the hobby of shell collecting

simple past tense and past participle of conceive

The doctrine, in the Roman Catholic Church, that the Virgin Mary was conceived biologically but free from original sin. / December 8th (The Feast of the Immaculate Conception of Mary).

(chemistry) the molality of a solution