Is a place where the five daily prayers are performed, but not the Friday prayer, considered a mosque, such that the obligation of prayer is waived for those who believe in the obligation of prayer in the mosque, or is it necessary for both the five daily prayers and the Friday prayer to be performed there for it to be considered so? And what are the conditions for a place to be designated a mosque?

A mosque where congregational prayers are held is not necessarily one where Friday prayers are held. Indeed, during the time of the Prophet, peace and blessings be upon him, Friday prayers were only held in his noble mosque, despite the existence of other mosques. The mosque is not a condition for the validity of congregational prayer, although performing congregational prayer in it is preferable. A mosque is a place designated for prayer, where the call to prayer is made and the five daily prayers are established. It is a waqf (endowment) dedicated for prayer, thus no longer owned by anyone, unlike a musalla (prayer area) which is used for prayer without being endowed.