Quick Reference

Meaning & Definition

先月 (sengetsu) is one of the most fundamental time expressions in Japanese, anchoring you within a relative timeframe that shifts with every month that passes. Unlike absolute dates, sengetsu resets your perspective automatically each month, making it the cornerstone of how Japanese speakers naturally reference the immediate past.

Sengetsu literally breaks down as 先 (before/previous) + 月 (month), creating a relative time marker that always means “the month immediately preceding the current one.” The critical distinction from English is that sengetsu is inherently relational—it gains meaning only in reference to 今月 (this month) as the anchor point. When you say sengetsu, you’re not naming a specific calendar month, but rather positioning an event against the present moment. This creates a dynamic timeframe: if today is July 15th, sengetsu refers to June; on August 1st, the same word sengetsu now refers to July. Japanese temporal reasoning fundamentally operates this way, using relative positioning (先→今→来→再来) rather than naming months by number. Sengetsu pairs naturally with particles like に (at a point in time) or から (starting from), allowing nuanced expressions of timing, duration, and sequence.

How to Use It

Avoid confusing sengetsu with 前の月 (mae no tsuki), which technically means the same thing but sounds more deliberate and descriptive—sengetsu is the natural choice in speech. Remember that sengetsu requires no article or additional qualifier in Japanese; “I did it sengetsu” is grammatically complete, whereas in English we must say “I did it last month.” When combining sengetsu with other time words (like 初め for “beginning” or 終わり for “end”), the particle に still governs the overall phrase: 先月の初めに (at the beginning of last month). Learners often hesitate with the nuance, but sengetsu is almost never used in negative or hypothetical contexts—use 前月 (previous month) or 去月 (last month, archaic in speech but used in formal writing) if you need a more neutral tone.

Example Sentences

Cultural Context

Japanese perceives time as a flowing continuum anchored by the speaker’s present moment, a linguistic feature called egocentric deixis. Sengetsu exemplifies this perfectly: the word itself contains no information about which calendar month is meant, yet Japanese listeners instantly understand because they contextualize it against “now.” This contrasts sharply with how English-speaking cultures sometimes absolutize time (naming months by number, referring to fixed dates). The relative system forces Japanese speakers to maintain awareness of temporal distance and perspective—sengetsu, 先週 (last week), and 先日 (the other day) all exist within a nested hierarchy of “not now.” This shapes how Japanese people discuss schedules, deadlines, and memories; relatedness to the present moment is grammatically encoded into every time reference.

The progression 先月 → 今月 → 来月 (last month → this month → next month) → 再来月 (the month after next) reveals the elegance of Japanese temporal symmetry. Each term is perfectly parallel, each carries equal weight in conversation, and each shifts automatically as time passes. This system appears throughout Japanese: 先年 (last year), 先々週 (two weeks ago), and even 先ほど (just a moment ago) follow the same pattern. Business Japanese relies heavily on this framework; meeting notes, project timelines, and financial reports in Japan organize information around sengetsu and its cousins because the system is unambiguous and universally understood. A learner who masters sengetsu’s true meaning—not just as a translation of “last month,” but as a marker of temporal proximity—unlocks intuitive understanding of how Japanese organizes time itself.

📚 Learn More