Mawson, C.O.S., ed. (1870–1938). Roget’s International Thesaurus. 1922.

Class II. Words Relating to Space
Section II. Dimensions
2. Linear Dimensions

208. Depth.

   NOUN:DEPTH; deepness &c. adj.; profundity, depression (concavity) [See Concavity].
  PIT, shaft, hollow, well, crater; gulf [See Interval]; deep, abyss, bowels of the earth, bottomless pit, hell.
  SOUNDINGS, depth of water, water, draft or draught, submersion; plummet, sound, probe; sounding-rod, – line; lead; bathometer, bathymeter, bathymetry; benthos; submarine, U-boat; depth bomb.
   VERB:BE DEEP &c. adj.; render deep &c. adj.; deepen.
  SOUND, heave the lead, take soundings; dig (excavate) [See Concavity]; plunge [See Plunge].
   ADJECTIVE:DEEP, deep-seated, deep-bosomed; profound, sunk, buried; submerged [See Plunge]; subaqueous, submarine, subterranean, subterrene [obs.], subterraneous; underground.
  knee-deep, ankle-deep.
  BOTTOMLESS, soundless, fathomless; unfathomed, unfathomable; abysmal; deep as a well; bathycolpian or bathukolpic or bathukolpian; deep-sea, benthal, benthopelagic; bathymetric, bathymetrical; bathypelagic, bathysmal; down-reaching, yawning.
   ADVERB:OUT OF ONE’S DEPTH; beyond one’s depth; over head and ears.
   QUOTATION:Under the whelming tide Visit’st the bottom of the monstrous world.—Milton