Yomam appears 51 times as a temporal adverb meaning 'by day' or 'in the daytime.' It is the correlative of layil (night) and together they form a merism for continuous time — 'day and night.' The word derives from yom (day) and frequently appears in contexts of God's constant guidance and protection, as in the pillar of cloud by day in the wilderness.
Yomam anchors a vital biblical theology of God's unceasing presence. The pillar of cloud guided Israel yomam (by day) while the pillar of fire guided them by night (Exodus 13:21) — together representing the Lord's 24/7 presence with His people. Psalm 42:8 declares 'By day [yomam] the LORD commands his steadfast love,' placing divine chesed in the framework of daily time. The New Testament echoes this in Christ's promise 'I am with you always, to the end of the age' (Matthew 28:20) — the eternal yomam of Emmanuel.