This is the 11845th most frequent German word.
theodor
"Theodor" is a German male given name, equivalent to "Theodore" in English.
In this sentence, 'Theodor' acts as a proper noun representing a person's name.
Theodor ist ein kluger Mann.
Theodor is a clever man.
Here, 'Theodors' is the possessive form of 'Theodor', indicating ownership of the book.
Theodors Buch liegt auf dem Tisch.
Theodor's book is lying on the table.
In this usage, 'Theodor' is used as a direct object, showing that the speaker observed a person named Theodor in the park.