definition given by wikipedia
In probability theory and statistics, the Jensen-Shannon divergence is a popular method of measuring the similarity between two probability distributions.
used as a similarity measure of entities in
Chen, J. and D. Ji, et al. (2006). Relation Extraction Using Label Propagation Based Semi-Supervised Learning. Proceedings of the 21st International Conference on Computational Linguistics and 44th Annual Meeting of the Association for Computational Linguistics, Sydney, Australia.