This is the 596th most frequent Czech word.
karel
"Karel" is a Czech male given name equivalent to "Charles" in English.
'Karel' here refers to a personal name used as the subject of the sentence.
Karel koupil nový telefon.
Karel bought a new phone.
'Karel' is used as a personal name in a possessive grammatical structure to indicate relations.
Můj strýc se jmenuje Karel.
My uncle's name is Karel.
'Karlem' here indicates the instrumental case form of the personal name 'Karel', showing accompaniment in Czech grammar.