Lesser Festivals are a type of observance in the Anglican Communion, including the Church of England, considered to be less significant than a Principal Feast, Principal Holy Day, or Festival, but more significant than a Commemoration. Whereas Principal Feasts must be celebrated, it is not obligatory to observe Lesser Festivals. They are always attached to a calendar date, and are not observed if they fall on a Sunday, in Holy Week, or in Easter Week. In Common Worship each Lesser Festival is provided with a collect and an indication of liturgical colour.

Source: Church of England website.