call upon (someone or something)

1. To choose, request, obligate, order, or demand someone to do something. Yesterday the president called upon world leaders everywhere to promote open and fair trade between countries. He was called upon to give testimony in court. Because I won that award, they called upon me to give the opening remarks at graduation.

2. To visit someone. I went to the East Coast last week to call upon my aunt. I'm sorry I'm late—I called upon Maggie after work because her mother just died. Now, when can we call upon you and meet the baby?

3. To access or make use of some helpful resource; to draw on something. I had to call upon all of my experience to fix the situation. The company has such vast financial resources to call upon that they are all but impervious to outside threats. After my husband died, I had to call upon all the resiliency I had left just to get out of bed in the morning.

call upon

1. To order or require someone to do something: I call upon you to tell the truth.

2. To make a demand or a series of demands on something: Social institutions are often called upon to assist the poor.

3. To visit someone: I called upon an old friend when I was in New York.

4. To make use of some resource; draw on something: I knew the task would call upon my every resource.