शिवः। Let us see the process of derivation of this word. There are several definition of the word शिवः। 1) शिवं मङ्गळमछ अस्ति अस्य इति शिवः, meaning one who has welfare, (or bliss or happiness). It could be interpreted as “as He has bliss, He gives bliss/happiness to us”. 2) श्यति अशुभम इति शिवः, meaning one who removes inauspicious/evil/misfortune. 3) शेरते अवतिष्ठन्ते अस्मिन् (सर्वे गुणाः/अणिमादिसिद्धयः वा) इति शिवः meaning ‘in whom all the qualities remain or the eight Siddhis such as ‘aNimA’. Thus, we have discussed the etymology of the शिवः as a whole.
There are etymologies that concentrate on each letter of the शिवः, i.e. शि and व। 1) शि is considered as a word though there one letter (consonant + vowel). This word शि is derived from the root शिञ् निशाने (meaning sharpening). So शिः means one who sharpens (our knowledge/intelligence etc.). The next letter वः is derived from the root वा गति-गन्धन-सुख-सेवनेषु meaning to move, to spread, to be happy and to serve. So वः means one who moves or spreads or is happy (and makes others happy) or serves. Comning these two words शिः and वहः we will get शिवः meaning one who sharpens our knowledge thereby makes us to move towards Him. 2) Another explanation to वकारः is it represents ‘air’ one of the five natural elements. (न, म, शि, व and य represent ‘earth’, ‘water’, ‘fire’, ‘air’ and ‘either’ respectively). So वकार in शिव has special connotation representing ‘air’ thereby the five letters represent ‘पञ्चीकरणप्रक्रिया’ (causing anything with the mixer of five elements0 suggesting that शिव is the creator of this world. Thus we get the meaning that शिवः is the master (kartA) of सृष्टि and लय । 3) शिव represents ‘शक्ति’ and ‘शिव’, thus the letter शि stands for ‘शक्ति’ and the letter व stands for ‘शिव’ himself as explained in agama scriptures. 4) In Agama scriptures, each letter in शिवः represents ‘बीजाक्षर’ that create power of positive vibration and this cannot be shown as etymology as it is based on self-experiement and experience. 5) शि stands for परब्रह्म and va stands for जीव, thus making the word शिव represents ‘ultimate soul’ and ‘soul (self).
There are a number of such explanation based on philosophical terms such as शिव represents ‘परमानन्द’ the ultimate bliss etc. Thus in the word शिव or in the mantra ‘namaH shivAya’, each letter has secret meaning in it. Few derivations/etymology have been shown here.