Sentence:  It was Giselle , the fille de chambre , come to clean the room , and while she stood before him with ears pricked up and regard all curiosity , explaining her <WSD>errand</WSD> , Alex could see from the corner of his eye the doctor doing all he could to calm the displeased bird . 
Meaning of the word marked with <WSD> tags:  a short trip that is taken in the performance of a necessary task or mission