Originally Posted by VVV
There is a difference between the etymological origin and the present meaning.
But maybe we should focus on the keris instead?
True Michael, so here is Websters present meaning:
1 : an object held to act as a charm to avert evil and bring good fortune
2 : something producing apparently magical or miraculous effects
At least to my way of thinking the purpose of making a sacrifice (perhaps not on the mundane level, but when dealing with spiritual matters) is in fact to bring about a "magical or miraculous effect".
So no Michael, i do not find the etymology of the words meaningless in this case.
Now, if we do return our focus to keris as you suggest, it is obvious that keris sajen have been used in the past as both a personal talisman to be keep and a sacrifical talisman to be, perhaps, thrown into a field in blessing. Just the fact that there are so many well preserved sajen that have been passed down as pusaka shows that many of them are meant to be kept, not "sacrificed" to the fields.