When Christians talk about worship they are referring to the practice of putting God first in their lives. This can be done either in private worship or in public worship - eg the Sunday church service.
Different Protestant denominations worship in different ways as part of their Sunday service, but there are also some common features to all. For example:
Worship centres on the Bible – reading the Bible, hearing preaching on it or discussing it.
Most churches include hymns or worship songs in the service.