About
Approximately
adverb
The kanji means promise, but the meaning of this word is about, which is a little different. Just think about promises. When you promise something you really need to follow through... but only about as much as you need to for the other person to be happy. Someone asks for a puppy for Christmas, and you get them a stuffed animal puppy. It's approximately the promise you made. Close enough. *wink*
The reading for this is actually the same one that you learned with the kanji, so no need to memorize anything new!
約三時間
about three hours
約半分
about half
約五十人
about fifty people
このゴボウの長さは約２メートルです。
The length of this burdock is approximately two meters.
今までで、約百万人の人がトーフグのフェイスブックページに「いいね」をした。
About a million people have liked Tofugu’s Facebook page so far.
その会社では約三年間働いていました。
I worked at that company for about three years.