I. noun
or cal·lous ˈkaləs
( plural callus·es -ləsə̇z ; or callous·es also cal·li -ˌlī)
Etymology: callus from Latin; callous, alteration (influenced by callous, adjective) of callus — more at callous (adjective)
1.
a. usually callous : a thickening of the horny layer of the epidermis as a result of friction or pressure : callosity 1a
b. usually callous : an area of skin so thickened : callosity 2
c. : the soft parenchymatous tissue from which new roots form in cuttings and which develops from the phloem or cortex or more frequently from the cambium itself over any cut or wounded surface of a stem or root, the outer cells usually becoming suberized or covered by a periderm
d. : a thickened area or protuberance on the surface of a plant : callosity ; specifically : the hard often hairy swelling from which the lemma and palea arise in grasses
e. : a growth of shelly material within or about the umbilicus of a gastropod shell
f. : a cuticular swelling on the body of an insect ; especially : one serving as a point of articulation for a wing
2. : a substance that is exuded around the ends of a broken bone and that by conversion into true bone bridges the gap and restores the continuity of the bone
3. usually callous : a protective condition of mental or emotional insensitivity
beneath my defensive callus of belligerence, I was filled with feelings of guilt — Harper's
4. botany : an accumulation of callose formed first as cylinders around the protoplasmic strands passing through the sieve plate and developing toward the end of the functional period of the sieve tube as a cushion or pad on each surface of the sieve plate
II. verb
( -ed/-ing/-es )
intransitive verb
: to form callus
transitive verb
: to cause callus to form on (as a cutting)