The word "synoptic" means to have a broad or wide view or perspective on something. It suggests looking at the big picture or considering multiple things together. Full definition
It has no parallel in the other Synoptic Gospels, but in John there is a similar incident (21:4 - 8) in connection with an appearance of Jesus to his disciples after his resurrection. (religion-online.org)
This may not justify the absolute claim that Thomas is independent of the canonical synoptic tradition, but it certainly justifies the acceptance of this as a working hypothesis, and hence the use of Thomas material, where relevant, in addition to the canonical material in an attempt to reconstruct the history of the tradition and to arrive at the earliest form of a saying or parable. (religion-online.org)
Using machine learning for discovery in synoptic survey imaging data. (nature.com)