The letter X is number 24 in the Latin English alphabet. X is the preferred letter used when symbolizing something unknown, not just in math where equations are commonly written as 5 + X = 12, but also in written language like "find X on the map", or "generation X". X can be traced back to an Arabic word meaning "thing". The reason X has Arabic roots is that it was used in early Arabic algebraic texts.
The letter X also has a history in the Ancient Greek language. It is commonly taken from the letter Xi. When it comes to Classical Greek, there are thoughts that it came from Chi.
The letter X is a very uncommon letter in the English alphabet and is commonly used to create a “sc” sound. This is usually when the letter is used before a vowel, which would usually give the C an S sound.
The letter X has one look, for both the upper case and the lower case. It is two diagonal lines that form a cross mark. There are times that X is used in other settings because of this – such as X marks the spot on a map or when it comes to the use of a cross.
X has only one tile in Scrabble, but drawing it is very lucky since its worth 8 points. It can be very difficult to place the X, especially if you already have other rare high scoring tiles on hand like Q and Z. However a few vowels will save the day, and if you get stuck there's always Scrabble Help for X to be had.