Disequilibrium occurs when

supply and demand are in balance.

supply and demand are out of balance.

supply coordinates with price.

supply coordinates with quantity.

Disequilibrium occurs when supply and demand are out of balance. However, this sometimes never happens to markets or it happens only rarely and momentarily. On the other hand, economists sometimes state that markets are always disequilibrium and that this is just how the market goes, as markets are excess in disequilibrium over extended periods of time.