How to say "fibre" in Japanese

• 繊維せんいJLPT N1approx.Common
  nounThe general word for fibre as a material or substance, whether textile, plant, muscle, or dietary fibre. When you simply mean fibre, this is the word to reach for.
  マイクロファイバークロスは、髪の毛かみのけの１００分ぶんの１という細ほそさの繊維せんいで編あみあげられたクロスです。↗

  Microfibre cloth is cloth woven from fibres as narrow as a hundredth of the width of a hair.
• ファイバーCommon
  nounThe loanword from English. It is not an all-purpose equivalent of 繊維: it belongs chiefly to technical and commercial contexts, and for fibre as a material it is seldom the word you want.

For fibre as a material or substance — textile, plant, muscle, or dietary — 繊維 is the word to use; 「ファイバー」 is the loanword, appearing mainly in technical and commercial contexts.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 繊維せんいfibre
• ファイバーfiber
• 筋すじfiber