This is the 1524th most frequent Turkish word.
gördüğü
"That he/she/it saw" or "what he/she/it saw."
The word "gördüğü" is a derivative of "görmek" (to see), combined with the possessive suffix, indicating "the one he/she saw."
Bugün gördüğü rüya oldukça garipti.
The dream he/she saw today was quite strange.
Here "gördüğü" refers to "the view he/she has seen," providing detail to the subject "manzara."
Gördüğü manzara nefes kesiciydi.
The view he/she saw was breathtaking.
This usage of "gördüğü" points to "the things he/she has seen," acting as a descriptor to "şeyler."