Matsya Purana — Solar–Lunar Motions
त्रय एव मुहूर्तास्तु काल एष स्मृतो बुधैः अपराह्णव्यतीताच्च कालः सायं स उच्यते //
traya eva muhūrtāstu kāla eṣa smṛto budhaiḥ aparāhṇavyatītācca kālaḥ sāyaṃ sa ucyate //
The wise have declared this period to be precisely three muhūrtas; and when the afternoon (aparāhṇa) has passed, that time is called sāyaṃ, the evening.
This verse does not discuss pralaya; it defines a practical division of daily time (muhūrta-based) used for orderly observance and ritual scheduling.
By defining evening as the period after the afternoon, it supports disciplined daily conduct—especially the proper timing for evening duties such as sandhyā, prayer, and routine dharmic observances expected of householders and rulers.
Its ritual significance is time-selection: identifying the evening window (three muhūrtas) helps fix proper timings for sandhyā and other rites, and can also guide auspicious scheduling (muhūrta) for ceremonies connected to building or consecration.