Extension
Addition
Synonyms Addition, adjunct, augmentation, appendage, annexe, supplementary building, add-on, addendum, supplement, appendix, wing, and ell.
Expansion
Synonyms Expansion, enlargement, broadening, diversification, augmentation, amplification, growth, elongation, stretching, increase, widening, deepening, heightening, enhancement, development, continuation, lengthening, and drawing out.
Prolongation
Synonyms Prolongation, increase, continuation, postponement, delay, more/extra time, additional time, lengthening, protraction, perpetuation, deferral, longer period, and increased time.
Example Sentences
The deadline received an extension.
She requested an extension politely.
The project needed an extension.
He installed a browser extension.
The house got an extension.