to lengthen is a form of:

Lengthen



verbpast tense: lengthened ; past participle: lengthened ; present participle: lengthening ;
1.
(INTRANSITIVE) Arms lengthen វែងឡើង, meetings lengthen បន្ដៗទៅ
Example: The days start to lengthen in March.
2.
(TRANSITIVE) (To make or become longer) បន្លាយ, សន្ធឹង, លាយទឹក, លូតវែង, បន្ដឲ្យវែង, បន្ដ, បង្កើន, ដំឡើងបៀវត្ស, កើន, ឡើង
Example: Mother had to lengthen Bangs dress, The shadows lengthen as evening comes on. lengthen a string បន្លាយ, lengthen trousers ធ្វើអោយ វែងឡើង, lengthen a meeting បន្ដពេល
ENGLISH MEANING
verbpast tense: lengthened ; past participle: lengthened ; present participle: lengthening ;
1.
(TRANSITIVE) To extent in length; to make longer in extent or duration; as, to lengthen a line or a road; to lengthen life; -- sometimes followed by out.
2.
(INTRANSITIVE) To become longer.
1.
attenuate, draw, elongate, extend, prolong, protract, stretch
1.
contract, shorten