(biology) Movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy.

(grammar) A participle indicating an ongoing or completed action or state in the active voice, where a noun modified by the participle is taken to represent the agent of the action denoted by the verb.

plural of active couple

(astronomy) A compact region at the center of a galaxy that has a much higher than normal luminosity over at least some portion, and possibly all, of the electromagnetic spectrum.

plural of active galactic nucleus

(physics) The mass of an object measured via the gravitational force that it exerts

plural of active dry yeast

plural of active gravitational mass

A form of yeast in which yeast cells in dehydrated granules are alive but dormant because of the lack of moisture.

That responds to spoken commands.