常・恒|つねtsune[1]atamadaka (head-high)

1. no-adjectiveusual state of things
   私は彼かれと学校がっこうに行いくのが常つねでした。↗

   I used to go to school with him.

• Related決まってきまってNeutralAdverb: 'every time, without fail', as in 「決まって遅れる」. Stresses that the same thing inevitably happens on each occasion; 「常」 is about a constant, normal state.
• Related常々つねづねWrittenAdverb for what one has long and consistently felt or done, as in 「常々思っている」; leans toward written prose.
• Related常につねにWrittenAdverb 'always, constantly', as in 「常に努力する」; same idea as 「いつも」 but leans toward written and formal prose.
• Related不変ふへんWrittenNoun for what is eternal and unchanging, as in 「不変の真理」; a written, academic-flavoured word stressing immutability rather than the normal state of things.
• RelatedいつもNeutralAdverb for 'always; usually' in daily life, as in 「いつもの道」; the everyday default, while 「常」 names the usual state itself.
• Related絶えずたえずNeutralAdverb 'ceaselessly, continually'; stresses that something goes on without interruption, rather than that it is the normal state.
• Related始終しじゅうNeutralAdverb and noun meaning 'from beginning to end; all along'; stresses the whole span of something, not the normal state of things.
• RelatedいつでもNeutralAdverb 'at any time; whenever you like'; stresses that something is possible whenever it is needed, not that it is the norm.
• Related不易ふえきWrittenWritten noun for what never changes through the ages, as in 「不易の真理」; also known from the haiku term 「不易流行」.
• Related常住じょうじゅうWrittenWritten noun with a Buddhist colouring, for permanent, unchanging existence or residence; literary rather than everyday.
• Antonym変へんNeutralAntonym: noun for change, or for what is strange and out of the ordinary; the direct opposite of the constancy of 「常」.

Use 「常」 for the constant, usual state of things, as in 「世の常」「常日頃」. For everyday 'always' use 「いつも」; for written 'constantly' use 「常に」, for long-held thoughts 「常々」, for 'every time without fail' 「決まって」, for 'ceaselessly' 「絶えず」; for change or the odd and unusual, the antonym 「変」.

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

1. (つね) いつも。いつもどおり。