昼行性(ちゅうこうせい)

Compound of 昼(ちゅう) ('daytime'), 行(こう) ('moving; acting'), and the suffix 性(せい) ('nature; property'). Used in biology and natural history to classify animals by their daily activity pattern. Almost always contrasted with 夜行性(やこうせい) ('nocturnal') and occasionally with 薄明性(はくめいせい) ('crepuscular').

Usage

• Most common in nature documentaries, biology textbooks, zoo exhibits, and pet-care articles.
• Typically appears as a predicate noun (犬(いぬ)は昼行性(ちゅうこうせい)だ) or as a modifier (昼行性(ちゅうこうせい)の動物(どうぶつ)).
• When discussing humans, the word often comes up in health articles warning that night-shift work disrupts our natural daytime rhythm.
• Also written 昼光性(ちゅうこうせい) (with 光(こう), 'light') in some biological sources, though 昼行性(ちゅうこうせい) is the standard form.

Common collocations

• 昼行性(ちゅうこうせい)の動物(どうぶつ): a diurnal animal
• 昼行性(ちゅうこうせい)である: to be diurnal
• 完全(かんぜん)な昼行性(ちゅうこうせい): strictly diurnal
• 昼行性(ちゅうこうせい)の生活(せいかつ): a daytime lifestyle
• 人間(にんげん)は昼行性(ちゅうこうせい)だ: humans are diurnal

Similar words

• 夜行性(やこうせい): nocturnal — the direct antonym; used for animals active at night such as owls, bats, and raccoons.
• 薄明性(はくめいせい): crepuscular — active at dawn and dusk; a narrower category between 昼行性(ちゅうこうせい) and 夜行性(やこうせい).
• 生活(せいかつ)リズム: daily rhythm; lifestyle rhythm — everyday word for people's daily routine; used when talking about humans rather than animal biology.
• 日中(にっちゅう)活動(かつどう): daytime activity — descriptive phrase; 昼行性(ちゅうこうせい) sums the same idea up as a single biological label.
• 概日(がいじつ)リズム: circadian rhythm — the broader biological 24-hour cycle underlying diurnal and nocturnal behavior.