Bold Letter
Bold, Bold Character, Bold Text, Boldface
noun, の adjective
What do you think a fat letter is? If I were to guess, I'd say a bold letter.
ふとじ
The reading for this one is a bit odd. The 太 uses the ふと from ふとい (kun'yomi) and the 字 is just the normal on'yomi reading for "letter." You have to remember this weird mismatched reading pair on your own, I'm afraid. Perhaps if you think about how fat letters don't really fit with the rest of the text, kind of like how the readings of both kanji also don't fit in it will help?
この字は太字にしてください。
Make this character bold, please.
マンションのエレベーターにのったら、でんこうけいじばんに赤い太字で「じしんです今すぐ外に出てください｣とかひょうじが出てきて、マジびびったよ。
When I got on the elevator in my apartment, the bold, red message appeared saying "Earthquake! Get out of this elevator right now," on the electric bulletin board so I got really scared.
太字にすることで、その言葉を強調しましょう。
Let’s put this in bold to add more emphasis.