it means the main or mostly used part in a song or the main theme
The term for a second melody that accompanies the main melody in a musical composition is called a "counterpoint."
It just means "melody". http://popularmusichistory.com/
I'm guessing you mean "unison."
In music, the term "contour" refers to the shape or direction of a melody, including how the pitch rises and falls. It describes the overall pattern of a musical line or phrase.
Unison
Harmonize is a musical term referring to the way a chord and melody are used together. You can make harmony with chords accompanied by melodies when created musical pieces.
In a vocal solo, the voice is the melody.
longated
Melody is the principle part of any tune, or air.
Quasi is an Italian musical term meaning: As if, resembling
The term "melody" refers to a sequence of musical notes that are perceived as a single entity, often forming the main theme of a piece of music. It is characterized by its rhythmic and tonal arrangement, making it memorable and recognizable. Melodies can vary in complexity and are fundamental to various musical styles and genres.
The term for the less significant notes that decorate a melody is "ornamentation." These notes enhance the main melody and add expressiveness, often including embellishments such as trills, grace notes, and mordents. Ornamentation enriches the musical texture and can vary in complexity depending on the style and period of the music.