Left radical is 'movement', right radical is 'around' (周). It orignally meant
to 'go around' or 'walk around', which it still may mean in Chinese.
Eventually, it came to mean 'cycle of time', and eventually 'week'; in Japanese
it only means 'week'. Henshall suggests as a mnemonic: 'Another week
Note: Henshall places this in the 3rd Grade kanji, as # 308. The Taka kanji database puts in the 2nd Grade kanji. Has the Jouyou kanji order been changed in the pat decade or so? This is the first discrepancy betwen the Taka databse and Henshall I've found.