Sat Sri Akal
Sat Shri Akaal or Sat Sri Akal (Punjabi: ਸਤਿ ਸ਼੍ਰੀ ਅਕਾਲ, sat śrī akāl) is a Sikh greeting in Punjabi (Sat = truth, Sri = great, Akaal = Timeless Being ie God). Complete usage is "Jo Bole So Nihaal, Sat Sri Akaal". It means roughly, "Blessed is the person who says 'God is Truth'". It is often abbreviated to "SSA" in modern communications (e.g. instant messaging, email, SMS, etc). It is so often used and so popular in Punjab that the Hindus and even many members of the tiny Muslim community use this as a greeting.
In Punjabi the greeting one uses is tied directly to the religion of the one being greeted. The proper greetings for Hindus is "Namaste" and for Muslims its "Assalam-o-Alaikum". If one does not know the religion of the person they are greeting, it is suggested that the neutral greetings Hello or Hi (both being emulated from English) be used.
"Sat Sri Akaal" is used by Sikhs throughout the world when greeting other Sikhs regardless of their native language. For instance, two members of the Punjabi Diaspora who exclusively speak English may still greet each other with this blessing, although this is by no means universal.
The usage of 'Sat Sri Akaal' as a greeting, although used by the majority of people who identify themselves as being Sikhs, is regarded as incorrect usage by Amritdhari (Orthodox) Sikhs, as the term is historically the second half of the Sikh war cry, "Joe Bolay So Nihal, Sat Sri Akaal", and is still used in the same way. As per the Sikh Rehat Maryada, or Code of Conduct, Amritdhari Sikhs greet each other with Waheguru Ji Ka Khalsa Waheguru Ji Ki Fateh, meaning "The Khalsa belongs to God, Victory belongs to God".
What is Sat ?
"Sat" is derived from word "satya" is a Sanskrit word that loosely translates into English as "truth" or "correct." It is a term of power due to its purity and meaning and has become the emblem of many peaceful social movements, particularly those centered on social justice, environmentalism and vegetarianism.
What is Sri or Shri?
Shri or Sri or Siri. Shri is a word which denotes respect just like the Punjabi words Ji or Sahib; also implies that the person or item is great or mighty.
What is Akal ?
Akaal or Akal is a word which refers to the undying and here "akaal" denotes "God". The word "Kal" is used to represent "Death" and A-Kal is the opposite of that - "that which defies death"
Why are hands folded
When the greeting Sat Sri Akal is said, it is said with folded hands. This reason is to show respect to the other party while the "name of God is being uttered". Also, Sikh's believe that God resides in all - so one is greeting the "God spirit" in the other person.
When two Sikhs meets they says Sat Sri Akal or Waheguru ji ka Khalsa, Waheguru ji ki Fateh with folded hand near the chest with head slightly bowed in a "humbling and respectful posture" bending forward and downwards keeping the legs straight - It is submission and respect for the Almighty Lord. So the greeting is both spoken and gesture or body language.
Thus it is both a spoken greeting and a gesture, a Mantr(a) and a Mudr(a). The prayerful hand position is a Mudr(a) called Anjali, from the root Anj, "to adorn, honor, celebrate or anoint." The hands held in union signify the oneness of an apparently dual cosmos, the bringing together of spirit and matter, or the self meeting the Self. It has been said that the right hand represents the higher nature or that which is divine in us, while the left hand represents the lower, worldly nature.