This is the 7648th most frequent Russian word.
жигулей
"Жигулей" refers to "Zhiguli cars," a brand of Soviet and Russian-made automobiles produced by AvtoVAZ.
Here, "жигулей" refers to the brand of the car (Zhiguli), in the genitive plural form indicating 'of Zhigulis'.
У меня есть старая модель жигулей.
I have an old model of Zhiguli.
In this context, "жигулей" still refers to the cars but in the genitive plural form numerically describing an unspecified quantity.
На улице я увидел много жигулей.
On the street, I saw many Zhigulis.
In this usage, "жигулей" denotes a thematic collection of vintage cars from the Zhiguli brand in a genitive plural construct.