The meaning of improve is to enhance in value or quality : How to use improve in a sentence. See examples of improve used in a sentence.
If you improve on a previous achievement of your own or of someone else, you achieve a better standard or result. We need to improve on our performance against france. Phrasal verb improve on/upon something (definition of improve from the cambridge advanced learner's dictionary & thesaurus © cambridge university press)
When you improve something, you make it better. For example, you can improve your harmonica playing with practice. Improve, ameliorate, better imply bringing to a more desirable state.
Improve usually implies remedying a lack or a felt need: To improve a process, oneself (as by gaining more knowledge). Improve on/upon [phrasal verb] improve on/upon (something) :
Definition of improve verb in oxford advanced american dictionary.