at least is an adverb meaning "if nothing else (`leastwise' is informal and `leastways' is colloquial)". It carries 2 recorded senses.
if nothing else (`leastwise' is informal and `leastways' is colloquial)
“at least he survived”
“they felt--at any rate Jim felt--relieved though still wary”
“the influence of economists--or at any rate of economics--is far-reaching”
colloquialism
not less than
“at least two hours studying the manual”
“a tumor at least as big as an orange”
Definitions, synonyms and semantic relations for at least come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.