Melody

n.joyful, calmeveryday

What it means

A recognizable sequence of musical notes heard as a coherent tune.

Reach for it when naming the part of music that listeners can follow or sing

The children carried the simple melody while the adults added harmony.

everyday
refrain
when a repeated musical or lyrical section is meant
not when A refrain includes repetition and often words, so it is not synonymous with melody.
everyday
tune
when a recognizable, singable sequence is meant
not when Tune is informal and can refer to the whole song rather than its melodic line.
professional
melodic line
when the continuing pitch sequence within a texture needs precision
not when The technical phrase is unnecessary for a simple standalone tune.
professional
motif
when a short recurring musical idea is the exact unit
not when A motif is usually shorter and less complete than a melody.
professional
theme
when a recurring musical idea helps organize a work
not when A theme can be rhythmic or harmonic and is not every melody.
professional
vocal line
when the melody assigned to a singer is central
not when This phrase excludes instrumental melody.
literary
air
for a simple songlike melody in traditional or historical contexts
not when Air is old-fashioned and easily confused with the atmosphere.
literary
strain
when a passage or distant fragment of melody is heard
not when Strain is archaic and also means pressure or injury.

The definition and the example on this page are written here. The dictionaries above ground which meaning is being described, not the wording.