Synonyms of diurnal

1 Syllable
set
2 Syllables
steadfast, daily, fixed, stable
3 Syllables
enduring, circadian, durable, perennial, persistent, perpetual, unchanging, continual, changeless, perduring, unfading, long-lasting, abiding, forever, permanent
4 Syllables
immutable, invariable, everlasting, perdurable
5 Syllables
imperishable, indestructible