What is the difference between Hajj and Umrah, and which one is performed first?

The difference between Hajj and Umrah (definition) in terms of ruling is that Hajj is a pillar of Islam and obligatory immediately upon the one who is able, whereas Umrah is a confirmed Sunnah (definition) or obligatory, depending on the differing opinions among scholars.

As for the difference in rituals, both share Ihram (definition), circumambulation (Tawaf (definition)), striving (Sa'i), and shaving or shortening the hair. Hajj adds standing at Arafat and stoning the Jamarat (definition).

If the question is about which one is performed first upon arrival in Mecca, it depends on the person's intention at the time of Ihram: - The Mutamatti': performs Umrah first, then deconsecrates. When the Hajj days arrive, he assumes Ihram from his location in Mecca and performs his Hajj. - The Mufrid: performs his Hajj first. Once he completes his Hajj, he exits to the nearest boundary of the Haram (definition) ( حل ) and assumes Ihram for Umrah. - The Qaarin: the rituals of Umrah are included in the rituals of Hajj. He performs the Tawaf of Arrival (Tawaf al-Qudum) and performs Sa'i for both Hajj and Umrah, remaining in his state of Ihram until he deconsecrates on the Day of Eid. A sacrifice (dam) is obligatory in this case, as it is also in the case of Tamattu'.