Sikhism
In Sikhism the word is used to refer to an action that one uses to remember and fix one's mind and soul on Waheguru.
The Sri Guru Granth Sahib informs “Remember in meditation the Almighty Lord, every moment and every instant; meditate on God in the celestial peace of Samadhi.” (p 508). So to meditate and remember the Almighty at all times in one's mind takes the person into a state of Samadhi. Also “I am attached to God in celestial Samadhi.” (p 865) tells us that by carrying out the correct practices, the mind reaches a higher plane of awareness or Samadhi. The Sikh Scriptures advises the Sikh to keep the mind aware and the consciousness focused on the Lord at all times thus: “The most worthy Samadhi is to keep the consciousness stable and focused on Him.” (p 932)
The term Samadhi refers to a state of mind rather than a physical position of the body. Although, it has to said that you can sit in mediation and also be in a state of Samadhi. The Scriptures explain: “I am absorbed in celestial Samadhi, lovingly attached to the Lord forever. I live by singing the Glorious Praises of the Lord” (p 1232) and also “Night and day, they ravish and enjoy the Lord within their hearts; they are intuitively absorbed in Samadhi. ||2||” (p 1259). Further, the Sikh Gurus inform their followers: “Some remain absorbed in Samadhi, their minds fixed lovingly on the One Lord; they reflect only on the Word of the Shabad.” (p503)
Read more about this topic: Samadhi