Grace is a name for any of a number of short prayer

Prayer

Prayer is a form of religious practice that seeks to activate a volitional rapport to a deity through deliberate practice. Prayer may be either individual or communal and take place in public or in private. It may involve the use of words or song. When language is used, prayer may take the form of...

s said or an unvoiced intention held prior to or after eating, thanking God

God

God is the English name given to a singular being in theistic and deistic religions who is either the sole deity in monotheism, or a single deity in polytheism....

 and/or the entities that have given of themselves to furnish nutrients to those partaking in the meal. Some traditions hold that grace and thanksgiving imparts a blessing which sanctifies the meal. In the English language tradition, reciting a prayer prior to eating is traditionally referred to as "saying grace".

A prayer of Grace is said to be an act of offering thanks to God for granting humans dominion over the earth, and the right and ability to sacrifice the lives of divine creations for sustenance; this thanks is the "saying of Grace" prior to and/or after eating of any meal.

However, in many indigenous cultures around the world, including North America, the saying of grace does not signify human dominion, but rather recognition of a plant or animal's giving their life and that some day the prayer giver, like every sentient being, will return to earth to give sustenance and life to others.

If one is not religious and the rest of the table is saying grace, it is considered polite and culturally appropriate to observe silently, or to bow one's head.