A group of people (sleepers) who inconspicuously remain dormant in a community until activated, by a prearranged signal, to perform acts of espionage, sabotage, and/or terrorism.

(cytology) The semipermeable membrane that surrounds the cytoplasm of a cell.

A spice ingredient used in cooking consisting of ground celery seed and salt.

The seed of the plant celery, Apium graveolens, used as a seasoning in cooking.

(energy) An electrochemical device in which the intrinsic chemical free energy of fuel and oxidant is catalytically converted to direct current energy.

(cytology) Any normal cell of an organism that is not involved in reproduction; a cell that is not on the germline.

The crisp, thick leafstalk of the celery plant; used as a vegetable, or eaten raw.

(cytology) A thick, fairly rigid, layer formed around individual cells of bacteria, Archaea, fungi, plants, and algae (but not animals and other protists which generally have cell membranes without cell walls). The cell wall is external to the cell membrane and serves a structural function helping the cell maintain its shape and protecting the cell from damage.

An enclosed underground space, often under a building, used for storage or shelter. / A wine collection, especially when stored in a cellar. / (slang) Last place in a league or competition.

(transitive) To store in a cellar.