The Refreshment Sundays or Rose Sundays are Sundays within the two major fasts

Fasting

Fasting is primarily the act of willingly abstaining from some or all food, drink, or both, for a period of time. An absolute fast is normally defined as abstinence from all food and liquid for a defined period, usually a single day , or several days. Other fasts may be only partially restrictive,...

 observed in Western Christianity

Western Christianity

Western Christianity is a term used to include the Latin Rite of the Catholic Church and groups historically derivative thereof, including the churches of the Anglican and Protestant traditions, which share common attributes that can be traced back to their medieval heritage...

, Lent

Lent

In the Christian tradition, Lent is the period of the liturgical year from Ash Wednesday to Easter. The traditional purpose of Lent is the preparation of the believer – through prayer, repentance, almsgiving and self-denial – for the annual commemoration during Holy Week of the Death and...

 and Advent

Advent

Advent is a season observed in many Western Christian churches, a time of expectant waiting and preparation for the celebration of the Nativity of Jesus at Christmas. It is the beginning of the Western liturgical year and commences on Advent Sunday, called Levavi...

. On these days, the fast was allowed to be relaxed, hence the name "Refreshment Sunday". Correspondingly, the liturgical colours

Liturgical colours

Liturgical colours are those specific colours which are used for vestments and hangings within the context of Christian liturgy. The symbolism of violet, white, green, red, gold, black, rose, and other colours may serve to underline moods appropriate to a season of the liturgical year or may...

 of the season are replaced with rose, hence the name "Rose Sunday".

The Refreshment Sundays are:

• Laetare Sunday
  Laetare Sunday
  Laetare Sunday , so called from the incipit of the Introit at Mass, "Laetare Jerusalem" , is a name often used to denote the fourth Sunday of the season of Lent in the Christian liturgical calendar...
  
  , the fourth Sunday in Lent
• Gaudete Sunday
  Gaudete Sunday
  Gaudete Sunday is the third Sunday of Advent in the liturgical calendar of the Western Church, including the Catholic Church, the Anglican Communion, the Lutheran Churches, and some liturgical Protestant churches...
  
  , the third Sunday in Advent

Of these, the better known is Laetare Sunday, and if reference is made to a single "Refreshment Sunday" or "Rose Sunday" it is usually this Sunday that is meant. It is also called Mothering Sunday

Mothering Sunday

Mothering Sunday is a Christian festival celebrated throughout Europe that falls on the 4th Sunday in Lent. Secularly it became a celebration of motherhood. It is increasingly being called Mother's Day, although in countries other than the UK and Ireland that holiday has other origins...

, Mother's Day, Rose Sunday, and Laetare Sunday

Laetare Sunday

Laetare Sunday , so called from the incipit of the Introit at Mass, "Laetare Jerusalem" , is a name often used to denote the fourth Sunday of the season of Lent in the Christian liturgical calendar...

.

As noted, on both Refreshment Sundays, the colour of vestments and church hangings is changed to rose. On Gaudete Sunday, where churches are using an Advent Wreath

Advent wreath

The Advent wreath, or Advent crown, is a Christian tradition that symbolizes the passage of the four weeks of Advent in the liturgical calendar of the Western church...

with purple candles, the candle for the third Sunday in Advent is also rose instead of purple.