humorous or whimsical verse that differs from other comic verse in its resistance to any rational or allegorical interpretation. Though it often makes use of coined, meaningless words, it is unlike the ritualistic gibberish of children's counting-out rhymes in that it makes these words sound purposeful.

It doesn't mean anything; it's a filler sound like la la la or "a-down-a-down-a-down-a" (Hamlet), used to keep the tune in old songs. Sometimes, an entire refrain was nonsense syllables.

A verbal imitation of a musical sound, as of the note of a lark or a horn.

Tirra lirra is a reference to a line found in Shakespeare's The Winter's Tale. It is from a song sung by Autolycus in Act IV. Scene III.

...For the red blood reigns in the winter's pale.
The white sheet bleaching on the hedge,
With heigh! the sweet birds, O, how they sing!
Doth set my pugging tooth on edge;
For a quart of ale is a dish for a king.
The lark, that tirra-lyra chants,
With heigh! with heigh! the thrush and the jay,
Are summer songs for me and my aunts,
While we lie tumbling in the hay...