givenName is a user attribute defined in RFC4519→ (Lightweight Directory Access Protocol (LDAP):Schema for User Applications). From RFC4519: "The 'givenName' attribute type contains name strings that are the part of a person's name that is not their surname. Each string is one value of this multi-valued attribute."
givenName is commonly used to transmit a person's first (given) name. Some IdPs may send multiple permutations of the person's name in the givenName attribute.