Particle

てにをは

tenioha

(word that does not obviously belong to any particular part of speech)

助詞

joshi

(word that does not obviously belong to any particular part of speech)

助辞

joji

(word that does not obviously belong to any particular part of speech)

粒子

ryūshi

(body with very small size)

素粒子

soryūshi

(physical object making up the constituent parts of an atom)