What is to grow large or larger; to be further extended; to expand; as, a plant enlarges by growth; an estate enlarges by good management; a volume of air enlarges by rarefaction called?

enlarge — To grow large or larger; to be further extended; to expand; as, a plant enlarges by growth; an estate enlarges by good management; a volume of air enlarges by rarefaction. (Webster's 1913.)

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