Tri-gate is generic term meaning the channel has gates on 3 sides of it (of 4 possible)

FinFET is one of the Tri-gate implementations.

I agree with you dear Tillmann Krauss, but I need some accurate classification with dimension for analysis.

FinFET is a generalized term used for any devices using silicon fin as body grown over an oxide substrate. basically GAA is not FinFET. whereas, Trigate MOSFET is just an implementation of Fin structure a more appropriate term would be Trigate FinFET, as MOSFET in present day is mostly associated with Non SOI structures such as Bulk MOSFET. details of the structural can be easily obtained in any renowned IEEE journal.

There is still a hot debate in academia  that are FinFETs and Trigate same or not?  However, many researchers consider FinFETs and TriGate as two different groups of devices such as "Lin C H, Chang J, Guillorn M, et al. Non-planar device architecture for 15nm node: FinFET or trigate?[C]//SOI Conference (SOI), 2010 IEEE International. IEEE, 2010: 1-2." , http://semiengineering.com/finfet-vs-tri-gate/, so FinFET and Trigates both are widely considered as part of a bigger group referred as multigate devices " https://en.wikipedia.org/wiki/Multigate_device", Therefore, in my oipinion maybe we cannot call Trigate as FinFET.  Some nice reviews "Bhattacharya D, Jha N K. FinFETs: From Devices to Architectures[J]. Advances in Electronics, 2014, 2014." and http://www.nature.com.sci-hub.io/nature/journal/v479/n7373/full/nature10676.html