Soft, gentle songs sung to calm and put babies or children to sleep.
From Middle English 'lullen' (to calm), combined with 'bye,' an imitative sound for soothing. 'Lulla' appears in many languages as a universal soothing sound.
Almost every human culture has lullabies with similar melting, repetitive patterns and low pitches because babies' brains are actually wired to respond to these specific acoustic features—a mother in Japan and a mother in Norway instinctively sing very similarly!
Complete word intelligence in one call. Free tier — 50 lookups/day.