expression
Used in superlative expressions with words like 一番, 最も, or 最悪 to mean 'the most ... so far' or 'the ...est yet'. It sets a time frame up to the present.
今までで一番おいしいラーメンだった。
That was the most delicious ramen I've had so far.
今までで最も難しい試験だった。
It was the hardest exam to date.