___
___ 先 [ahead]
also in   ___
On-reading: セン as in 先日 senjitsu ___
SEN saki ahead | before | forward  
More on this Kanji at https://www.kanjijump.com/dict/先
先生 sensei teacher | master  
先日 senjitsu the other day  
先月 sengetsu last month