7 days of the week, 4 moments of the day.
Six of the seven days end in -di: lundi, mardi, mercredi, jeudi, vendredi, samedi — only dimanche (Sunday) breaks the pattern. They're also not capitalised in French (unlike English).
The four moments of the day: matin (sunrise to noon), après-midi (noon to ~6pm), soir (~6pm onwards — equivalent to English "evening" AND "tonight"), nuit (the night as a period — sleeping hours, late-night hours). The English "tonight at 9pm" maps to French ce soir à 21h, NOT cette nuit. Bonjour for matin/après-midi, bonsoir for soir, bonne nuit only at bedtime.
Which French word matches?