The main difference between a concerto and a symphony is a musical piece that has several segments that normally involves an orchestra whereas a concerto is a piece that has three movements which include a soloist and an orchestra.
A concerto is a musical piece in which there is a solo instrument that is accompanied by an entire orchestra. This is the modern understanding of the concerto. It became popular in the Baroque period along with the concerto grosso in which a small group of instruments is accompanied by an orchestra. There are many different concertos like violin concertos, piano concertos, cello concertos to name a few. Each will feature an expert on the solo portions of the work. A violin concerto for instance will feature a skilled violinist for the solo. A symphony is an extended piece of music for an orchestra.
A concerto is a musical piece in which there is a solo instrument that is accompanied by an entire orchestra. This is the modern understanding of the concerto. It became popular in the Baroque period along with the concerto grosso in which a small group of instruments is accompanied by an orchestra. There are many different concertos like violin concertos, piano concertos, cello concertos to name a few. Each will feature an expert on the solo portions of the work. A violin concerto for instance will feature a skilled violinist for the solo. A symphony is an extended piece of music for an orchestra.