Sat Sri Akaal

Sat Sri Akaal (Gurmukhi: ਸਤਿ ਸ੍ਰੀ ਅਕਾਲ, ) is a Jaikara (lit. Call of Victory) now used, often, as a greeting by Sikhs. It is the second half of the Sikh Clarion call, given by the Tenth guru, Guru Gobind Singh, "Bole So Nihal, Sat Sri Akal" (Shout Aloud in Ecstasy. Truth is the Timeless One).

Meaning
Sat is a Punjabi word, which means truth, from the Sanskrit word Satya (सत्य). Sri is a honorific used across various Indian Subcontinent languages. Akaal is made up of the Punjabi word Kal, meaning time, and the prefix a- which is used in various Indian languages as a way to make a word into its antonym, so Akal means timeless.

Usage
Besides being the clarion call of Sikhism, the Jaikara has become an integral part of the Sikh liturgy and is spoken at the end of Ardas, the Sikh prayer in holy congregations.

The usage of Sat Shri Akaal as a greeting, although used by the majority of people who identify themselves as being Sikh, is regarded as incorrect usage by "Amritdhari [baptized] Sikhs. As the term is historically the second half of the Sikh war cry, "Bole So Nihal, Sat Shri Akal", 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 the Lord God! The victory belongs to God!".

Defense battle cry
Three regiments of the Indian Army – the Punjab Regiment, Sikh Regiment, and Sikh Light Infantry – use it as their battle cry.

Akaal Sahai
Akaal Sahai (Gurmukhi: ਅਕਾਲ ਸਹਾਇ, pronounced Akāl Sahai, lit. With God's Grace) is a traditional greeting, used by Sikhs. It was used as a national motto during the period of the First Sikh State, Sikh Confederacy, and Sikh Empire. It was also used a lot on the puratan Sikh shastars normally found on the blade or inside the hand guards.