Settling and deciding with 定
The kanji 定 means decide or fix. In compounds, it can also describe something stable.
Etymology
This kanji is a phono-semantic compound comprised of 宀 (roof) as the semantic component and 正 (straight/correct) as the phonetic component, giving the on-reading テイ.
Visualize placing things under a roof and arranging them in orderly fashion, settling everything into its proper place. Just as objects set under a roof in proper order stay put, a decision or fixed arrangement remains in place.
Judgments
断定 (Definite conclusion)
断定 means stating or judging something as definite.
It combines 断 (decide firmly) with 定 (fix) to show a firmly fixed conclusion.

Inspector Megure suggests the murder suspect committed suicide by drowning himself. The medical examiner disagrees.
- 監察医
( : - 「ですが死因
( は溺死( ではありません…」- “However, drowning wasn't the cause of death...”
- 目暮
( : - 「え?」
- “What?”
- 監察医
( : - 「解剖
( してみないと断定( できませんが… おそらく毒物( を飲( んだあと池( に入( ったものと…」- “I can't say for certain without an autopsy... but it's likely he took poison and then entered the pond...”
Specification
特定 (Specification)
特定
It combines 特 (particular) with 定 (fix) to show fixing on one specific thing.

A student from a lower grade enters the classroom. She stops and stares at Asuka Jr., one of the boys in the class.
- 涼子
( : - 「ある特定
( のところに集中( してない? しかも」- “Isn't she focused on one particular area? And on top of that...”
- 恭子
( : - 「ものすごく信
( じがたいところに……」- “It's in a frightfully hard to believe area...”
限定 (Limitation)
限定
It combines 限 (limit) with 定 (fix) to show something fixed within clear bounds.

Takeo and Rinko meet up after school and stop somewhere for a drink and to chat. Rinko brings up February 14th, which is right around the corner.
- 凛子
( : - 「もうすぐバレンタインだから限定
( チョコいっぱい出( てるよねー」- “Since it's almost Valentine's, a lot of limited edition chocolates have come out.”
Stability
安定 (Stability)
安定
It combines 安 (peaceful) with 定 (settled, fixed) to show a peacefully settled state.

Coco and her friends are trapped in a maze and trying to find a way past a dragon. Seeing the others working out magic to use, Coco tries her hand at a spell, creating a flame. Agott isn’t impressed, but Tetia feels otherwise.
- テティア:
- 「炎
( が安定( してる!」- “The flame is stable!”
- 「前
( はすぐ落( ちて燃( え尽( きちゃってたのにいつの間( に!?」- “It used to go out and burn out right away, so when did this happen!?”
- “The flame is stable!”