We found 18 dictionaries that define the word lengthening:

General (15 matching dictionaries)

1. lengthening: Merriam-Webster
2. lengthening: Collins English Dictionary
3. lengthening: Vocabulary.com
4. Lengthening, lengthening: Wordnik
5. lengthening: Cambridge Advanced Learner's Dictionary
6. lengthening: Wiktionary
7. Lengthening, lengthening: Dictionary.com
8. lengthening: Cambridge Essential American English Dictionary
9. Lengthening: Online Plain Text English Dictionary
10. lengthening: Rhymezone
11. Lengthening: AllWords.com Multi-Lingual Dictionary
12. lengthening: Webster's 1828 Dictionary
13. lengthening: FreeDictionary.org
14. lengthening: Mnemonic Dictionary
15. lengthening: TheFreeDictionary.com

Business (1 matching dictionary)

16. lengthening: Legal dictionary

Computing (1 matching dictionary)

17. lengthening: Encyclopedia

Medicine (1 matching dictionary)

18. lengthening: Medical dictionary

(Note: See lengthen as well.)

Definitions from Wiktionary (lengthening) ▸ noun:  The process of making or growing longer. ▸ noun:  (phonology) a type of sound change when a sound (especially a vowel) lengthens Similar: increasing, prolongation, protraction, perpetuation, propagation, regrowth, upgrowing, multiplication, progradation, prosification, more... Opposite: shortening, reducing, shrinking, contracting Types: dilation, extension, enlargement, more... Phrases: compensatory lengthening, crown lengthening, bone lengthening, lengthening reaction, lengthening contraction, more... Adjectives: compensatory, final, progressive, gradual, apparent, slight, further, surgical, tibial, significant, relative ▸ Words similar to lengthening ▸ Usage examples for lengthening ▸ Idioms related to lengthening ▸ Wikipedia articles (New!) ▸ Popular adjectives describing lengthening ▸ Words that often appear near lengthening ▸ Rhymes of lengthening ▸ Invented words related to lengthening