What is the diffenece between showers and rain

As written above, it is a question of time. Rain is usually lasting for hours. Showers is intermittent, with perhaps some sunshine in-between.

A constant rain often happens along a warm front where rain showers happen along a cold front. This is because, as the cold air lifts the warm one from under, it creates unstable air masses with isolated cumulonimbus clouds with rain showers under them.

showers are very light and barely make a difference and dont last for long, rain is heavier and lasts longer usually