Simple past tense and past participle of lengthen.(verb)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "lengthened" in a sentence
"As the term lengthened the girls were pushed harder and harder by the instructors, and Bess and others like her complained a good deal."
"As Warren relayed, the homeowner was sophisticated enough to recognize that his interest rate would be doubled and his term lengthened so that he would in fact lose his home sooner and the lender would own his valuable property."
"-- If the appropriation were so given the University would be destroyed and the public school term lengthened a day and a half."