Grace is a word with many meanings. In religious contexts, it often refers to the free and unmerited favor of God. But the word can also refer to simple elegance or beauty, or even to a kind of good fortune.
In science, grace has a different meaning. It is often used to describe the smoothness with which an object moves through space or time. A ballerina might be described as moving with grace, for example. Or a planet might be said to orbit its star with grace if its orbit is nearly circular and not too elliptical.
Grace can also refer to the way in which an object appears to defy gravity. A feather falling slowly through the air might be described as havinggrace, while a rock tumbling down a hill would not be said to have grace.
Finally, in some scientific fields, grace is used as a synonym for mercy or forgiveness. If someone makes a mistake and they are given grace, it means that they are forgiven and will not be held accountable for their actions. This usage is most common in psychology and sociology.