The word is - geoch. Apparently it means something like - giddy up, but I don't know. Here's the context - it comes from the children's book 'An tÁilleán'.

Geoch, geoch a chapaill bhig,
Geoch i lár an bhóthair,
Féach an oidhche ag druidim linn,
Is d'imthigh an tráthnóna. srl srl

geocach : stroller, vagabond ;
geócaíghim: to stroll, act as a vagabond ;
Molaim dhuit leagan de fhoclóir O' Brien ó 1798 ,1832 a íoslódáil mar is foinsí iontacha iad don teanga.

Go raibh maith agat. Here's the rest of the rhyme - in the picture there's a little girl running in the middle of the road with a boy, I imagine he must be her brother - running behind her, holding a loop of string attached to her as if he were holding the reins of a horse. He also has a whip. They're both smiling and seem to be enjoying themselves. He is barefooted. The first capital letter G of the rhyme also has a child riding on top it, as if they were riding a horse.

An 'mdhó míle as so go Corcaigh thear?
A ceathair is trí sgór glan.
Geoch, geoch a chapaill bhig,
Is geoch i lár an bhóthair.

An mbéimíd ann roimh oidhche, a chuid?
Och, béir i n-am do dhóthain.
Geoch, geoch a chapaill bhig,
Is geoch i lár an bhóthair

Míle míle beannacht leat,
Go dtéidh tú slán a stóraigh!
Geoch, geoch a chapaill bhig,
Is geoch i lár an bhóthair!