To Make Something Hard
To Harden Something, To Strengthen Something
transitive verb, ichidan verb
This word consists of kanji with hiragana attached. Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means hard so the verb vocab version? To make something hard. You need to differentiate this from 固まる, though, which means "to harden" (the hardening happens on its own). This word means "to make something hard," because you're doing the hardening. You can remember this because you want to make something hard. And to do that, you send special "mail" (める) to this thing you want to make hard, and this mail does that for you.
Since the reading for 固 (かた) is different than the one you learned with the kanji, here's a mnemonic to help you:
Why would you want to make something hard? Obviously because you want to put it in a catapult (かた). There's no point putting soft things in catapults, after all.
まず固める
to harden something first
がっちり固める
to firmly harden something
しっかり固める
to properly harden something, to harden something well
ゼラチンで固める
to harden with gelatin
セメントで固める
to harden with cement, to reinforce with cement
コンクリートで固める
to harden with concrete, to reinforce with concrete
足場を固める
to secure a solid foothold, to secure one's position
決意を固める
to harden one's resolve
足元を固める
to firmly plant one's feet on the ground, to secure a solid foothold
ねん土は熱で固めることができるよ。
You can harden clay with heat.
ビエトは毎朝一時間かけてリーゼントをワックスで固めます。
Viet takes an hour to make his pompadour hard every morning.
コウイチは、日本に軍隊を派遣する決意を固めた。
Koichi decided to strengthen his position and send his troops to Japan.