Chutney comes from the Indian "chatni",
which means "strongly spiced". Normally, it is made out of fruit pieces,
vinegar, sugar, peppers and/or other spices.
Chutney is nice with Indian food but also as a replacement of mustard
with cheese.
Relish is Or less the same as chutney; the cooking time
may be a bit shorter though. Therefore, chutney is normally softer and
the sugar may be caramelized.
Salsa has most probably an Aztec Indian
background and is made of tomatoes and chillies as main ingredients.
Salsa means "sauce". Salsa is cooked shortly and is not sweet or caramelized.