thickening

noun

1. (countable, uncountable)The process of making something, or becoming, thick or viscous.
2. (countable, uncountable)A substance, usually a source of starch, used to thicken a sauce.
3. (countable, uncountable)A thickened part of a structure.

   “[…] the inner layer (of nearly equally large cells) lacks the regular semiannular or annular thickenings of most other leafy liverworts […]”

   “They disappear at once on slightly relaxing the air-pressure, whilst true incipient thickenings of the surface remain white and unpliably stiff.”

verb

1. (form-of, gerund, participle, present)present participle and gerund of thicken

adj

1. (not-comparable)Beginning to thicken, becoming thicker.

   “From Keighley onwards we had obviously returned to civilisation, for the surrounding country was now studded with the sodium street lights of suburbia and a thickening industrial haze was blotting out the moon.”