Thanks for answering that question. The question about Glasgow Celtic stems from the Scottish club's cultural history.
You see at the turn of the century many Irish came to Glasgow searching for work after the potato famine. The Irish immigrants got together to raise money for the poor catholics in Glasgow and decided to erode the name Celtic (pronounced KEL-TIK) and go with Celtic to combine Scottish Gaelic with Irish Gaelic. It is a rarity that the word Celtic is pronounced with an "S" sounding consanent.
The original new york Celtics may will be from the famous notion of Glasgow Celtic as every irishman across the globe at that time founded a rugby, soccer, or something under that name.