Origin: Latin suffix -ate
At any rate has 3 different meanings across 2 categories:
used to indicate that a statement explains or supports a previous statement
"Anyhow, he is dead now"
"I think they're asleep; anyhow, they're quiet"
"I don't know what happened to it; anyway, it's gone"
"anyway, there is another factor to consider"
"I don't know how it started; in any case, there was a brief scuffle"
"in any event, the government faced a serious protest"
"but at any rate he got a knighthood for it"
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"
In any case, anyway, anyhow, regardless; used to discard or qualify a previous thought.