ཕྱག་ - phyag - hand, honorific

 ཕྱག་ phyag (Sanskrit pāni) is the honorific word for hand. The non-honorific word is ལག་པ་ lag pa. In addition to addressing a higher being, teacher or parents' hands, it's also used in various expressions.  ཕྱག་ could refer to prostrations or homage where the longer word is ཕྱག་འཚལ་ or ཕྱག་འཚལ་བ་ phyag 'tshal ba .  འཚལ་ means beseech, ask, or please... do something. You see this expression used a lot for homages to various holy beings such as སྨོན་ལམ་ prayers and also as the initial homage in commentaries (that is often used to classify the commentary into one of the སྡེ་སྣོད་གསུམ་) 

ཕྱག་་འབུལ་ phyag 'bul means to offer an homage with the hands (salutation). འབུལ་ is the verb for offering or presenting.

You could also encounter this with various tantric deities that have specific amount of arms, such as ཕྱག་བཞི་པ་ (could defer to the four-armed Avalokiteshvara or to other deities with four arms).

ཕྱག་རྒྱ་ phyag rgya is a hand-sign (mudra), or a seal. The word for Mahamudra is ཕྱག་རྒྱ་ཆེན་པོ་, great seal.

ཕྱག་ལས་ phyag las is the honorific word for ལས་ཀ་ las ka, work.

Vajrapāni, holder of the vajra, is ཕྱག་ན་རྡོ་རྗེ་ phyag na rdo rje.

More examples of ཕྱག་ in various translations:

ༀ་རྗེ་བཙུན་མ་འཕགས་མ་སྒྲོལ་མ་ལ་ཕྱག་འཚལ་ལོ། 

om jetsünma pagma drölma la chaktsal lo 

OṂ Obeisance to Tārā, revered and exhalted. 

།ཕྱག་འཚལ་ཏཱ་རེ་མྱུར་མ་དཔའ་མོ། །ཏུཏྟཱ་རེ་ཡིས་འཇིགས་པ་སེལ་མ། 

chaktsal taré nyurma pamo tuta rayi jikpa selma 

Homage to Tārā, swift and courageous who dispels all fears with the mantra TUTTĀRE, 

ཉམས་ཆག་ན་རཀ་སྦྱང་ཕྱིར་ཕྱག་མཆོད་བཞེས༔

nyamchak narak jang chir chakchö shyé

And accept our prostrations and offerings, so that we may purify impairments and breakages, and even the lower realms.

འཇིག་རྟེན་ན་དགྲ་བཅོམ་པ་རྣམས་ལ་ཕྱག་འཚལ་ལོ། །

jikten na drachompa nam la chaktsal;

Homage to the arhats in this world.

ཞལ་གཅིག་ཕྱག་གཉིས་སྐྱིལ་ཀྲུང་བཞུགས། །

shyal chik chak nyi kyiltrung shyuk

With one face, two hands and is seated in cross-legged posture,

འཕགས་པ་འཇམ་དཔལ་ལ་ཕྱག་འཚལ་ལོ༔

phakpa jampal la chaktsal lo

Homage to Noble Mañjuśrī!

སློབ་དཔོན་ཆེན་པོ་ས་ར་ཧའི་ཕྱག་རྒྱ་ཆེན་པོ་འདི་ལ་དོན་བཞི་སྟེ། 

lobpön chenpo sara hé chakgya chenpo di ladön shyi té

This mahāmudrā of the great master Saraha has four topics:

ཞལ་གཅིག་ཕྱག་བཞི་སྐུ་མདོག་དཀར་ལ་འཚེར༔

shyal chik chak shyi kudok kar la tser

Brilliant white in colour with one face and four hands—

རང་ཤེས་འཁྲུལ་པ་བྲལ་བའི་བརྡ་ཕྱག་གར༔

rang shé trulpa dralwé da chak gar

Are oneself, free from confusion I prostrate symbolically.