Argilaceous

Part of speech: adjective

Definitions

1. Relating to or composed of clay or clay-like materials; having the properties or characteristics of clay; describing soils or rocks that are rich in clay content
2. Pertaining to earth substances primarily consisting of fine-grained clay minerals; exhibiting qualities typical of clay such as plasticity and cohesiveness; characterizing sedimentary deposits containing significant clay fractions
3. Constituting or resembling clay in texture and composition; indicating the presence of clay particles within soil or rock; used to describe geological or soil materials that are predominantly clayey in nature

Etymology: Clay was named for its color. The Greek "argillos" meant white clay, and it came from the same root as "argos," meaning bright or shining. That root also gave Latin "argentum," silver, which suggests the ancient sense was of something pale and gleaming. Latin adopted the Greek noun as "argilla," and derived the adjective "argillaceus" from it, meaning clay-like. English took the adjective directly from Latin, with its "-aceous" ending marking "of the nature of" or "resembling," as in "herbaceous." The result is a learned, technical term: a rock or soil "argillaceous" in character is one whose composition is mostly clay.

Synonyms: clayey, muddy, argillaceous

Antonyms: sandy, gritty