What does "lengthening" mean?

The process of making or growing longer.

How do you pronounce "lengthening"?

Pronounced //ˈlɛŋ(k)θənɪŋ//.

Common synonyms include: prolongation, cell elongation, continualness, continuance, continuation, continuity.

/ˈlɛŋ(k)θənɪŋ/ noun, verb

noun, verb ·Moderate ·College level

Noun

1
The process of making or growing longer.
"This enabled an additional 15-20 containers to be carried per train, giving a 20% productivity gain, and was partly enabled by Network Rail completing the lengthening of loops on the route northwards from Southampton via Banbury."
2
the act of prolonging something wordnet
3
a type of sound change when a sound (especially a vowel) lengthens

Verb

1
present participle and gerund of lengthen form-of, gerund, participle, present

"Growing seasons are lengthening."

From lengthen + -ing.