Proto-Indo-European Roots

Root/Stem: *pó- / *pí-
Meanings:  to drink
Hellenic Greek pínó 'I drink, Aeolian & Doric pónó 'I drink'; potos 'a drink'
Italic Latin pótáre 'to drink hard', potus 'a drinker', Old Latin pócolom 'a glass';
Latin bibere 'to drink', bibó 'I drink' < *pibó; >
Sardinian biere, French boire, Occitan beure, Spanish beber, Catalan beurer, Italian bevere, Ladin baiver, Romanian a bea, Portuguese beber
Celtic Common Celtic *ibó 'I drink' >
Old Irish ibim 'I drink', Middle Irish ibh, Irish ibhim, Old Welsh iben 'we drink', Welsh yfed 'to drink', Cornish evaf, Breton eva
Indic Vedic pipaté 'he drinks', Sanskrit páti 'he drinks', pítis 'a drink'
Marathi pine 'to drink', Gypsy peav, Lahnda piwen, Nepali piunu, Gujarati piwu, Punjabi & Hindi pina
Anatolian Hittite paš- 'to swallow' < *pó-
Balkan Thracian pinon 'a drink',
Albanian 'drink!', aorist piva 'I drank'
Baltic Lithuanian puota 'a drink', Old Prussian poutwei, púton 'to drink', poieiti 'drink!' (pl.)
Slavic Common Slavic *piti 'to drink', *pijo. 'I drink', caus. *pojiti 'to give to drink' >
Bulgarian pija 'I drink', Macedonian pijam, Belorussian pic 'to drink', Czech & Serbo-Croatian & Slovene piti, Slovak & Russian pit', Polish & Upper Sorbian pic', Lower Sorbian pis'
Notes: The simplest lexicon of the ancient humanity consisted of names for relatives, animals, plants, sky objects, and verbs of the most common actions, like this one: 'to drink'. This is why it is rather stable in the Indo-European family, and its cognates can be found practically everywhere except Germanic and Iranian.
The two variants of the root hardly used be different semantically.