1.
particles, postpositional particles
A collective term for Japanese grammatical particles (て, に, を, は, etc.).
2.
fine points of language, wording details
By extension, the subtle details and nuances of how something is worded or phrased.
Etymology
The name comes from the particles て, に, を, は — four of the most common Japanese particles. The term dates back to classical Japanese grammar studies.
Usage
In sense 1, used when discussing Japanese grammar, especially particle usage. In sense 2, used more broadly to mean the subtle details of phrasing and word choice, particularly in formal writing.