Apócope

Spanish shortened form of a word

Apocope is the suppression of some letters at the end of a word.

It can be seen applied to different types of words, for example adjectives, adverbs, numbers, and nouns.

Here are some examples:

bueno → buen: buen día
good day

malo → mal: mal augurio
bad omen

grande → gran: gran elefante
big elephant

santo → san: San Antonio 
Saint Anthony

primero → primer: primer día
first day

fotografía → foto  
photo → photography

kilogramo → kilo  
kilo → kilogram

Let me take a look at that...