溫故知新

to review the old and know the new (idiom, from the Analects) / to recall the past to understand the future

surname Wen

warm / lukewarm / temperature / to warm up / mild / soft / tender / to review (a lesson etc) / fever (TCM) / old variant of 瘟[wen1]

happening / instance / reason / cause / intentional / former / old / friend / therefore / hence / (of people) to die, dead

a close friend over many years

to know / to be aware

abbr. for Xinjiang 新疆[Xin1 jiang1] or Singapore 新加坡[Xin1 jia1 po1] / surname Xin

new / newly / meso- (chemistry)