This is the 16019th most frequent Polish word.
trzymają
"Trzymają" means "they hold" in English.
In this sentence, 'trzymają' is present tense 3rd person plural of 'trzymać' (to hold), describing the physical action of holding.
Oni trzymają książki w rękach.
They are holding books in their hands.
Here, 'trzymają' metaphorically refers to maintaining or keeping, describing the action of sustaining relationships.
Oni trzymają dobre relacje ze swoimi sąsiadami.
They maintain good relationships with their neighbors.
In this usage, 'trzymają się' indicates the act of sticking together or supporting one another.