the whole week; all week
Emphasizes the entire week without interruption; often used with verbs like 休む, かかる, 続く.
It rained for the whole week.
He took the whole week off.
一週間 simply means 'one week', while 丸一週間 emphasizes the entire duration without exception.
Compound of 丸 (まる, 'whole, complete') + 一週間 (いっしゅうかん, 'one week').