Meaning: Trick, Bone
The knack for handling things effectively
“Kotsu” is most commonly used to refer to the knack or know-how for handling things effectively, similar to the meaning of “trick.”
When using “kotsu” in a sentence, it is typically written in katakana as “コツ” rather than hiragana.
Expression:Kotsuwo tsukamu (コツをつかむ)
Yes, the word “kotsu” can be used on its own to mean “knack” or “trick,” but it is also often used in the expression “kotsu wo tsukamu,” which means “to grasp the knack” or “to get the hang of it.”
・”私はボールの蹴り方のコツをつかんだ！”(Watashiwa bo-runo kerikatano kotsuwo tsukanda!)
“I have grasped the knack of how to kick a ball!”
“フォートナイトのゲームを攻略するために、コツをつかむのに時間がかかっている。”(Fortnite no gamewo kouryakusurutameni kotsuwotsukamunoni jikanga kakatteiru)
“It’s taking me some time to get the hang of playing and conquering Fortnite.”
The bones of a cremated person.
You are correct that “kotsu” means “the bones of a cremated person.” In this case, it is more polite to use the word “okotsu,” which includes the honorific prefix “o.” However, this usage is not very common in daily conversation.
“I collect the bones of a cremated person.”