Post
noun
Mail (or post) has convenience because it is sent for you in the mail (or the post!).
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. The reading of 便 (びん) in this vocabulary is an exceptional reading, so here's a mnemonic to help you out. You get a lot of junk mail so you throw it in the waste bin (びん). The waste bin is where junk mail goes.
おくさーん、郵便ですよー！
Madam, we have mail for you!
郵便業においては、効率とスピードが全てだ。
Efficiency and speed are everything in mail service.
こう空郵便で送るか、船便で送るかまよっています。
I wonder if I should ship this by airmail or sea mail.