En- (an intensifying prefix) + lengthen (to extend, to protract).
enlengthen (third-person singular simple present enlengthens, present participle enlengthening, simple past and past participle enlengthened)
- To lengthen, to render or become longer.
1971, Arun Mukhopadhyay et al, Agricultural Extension: A Field Study, page 6:
- However, recent trends in mortality and changes in social attitudes tend to depress the proportion of widows, enlengthen the exposure period of married…