A
You can tune to any note you wish, most common being A. Guitar's tuning being: EADGBE from strings 6 to 1
The standard tuning note for the guitar is E.
A standard symphony orchestra can tune to three different members: the principal oboe, the concertmaster, or the solo pianist. The oboist is used to tune whenever there is an oboe in the orchestra, the concertmaster is used whenever there isn't an oboe, and the pianist/keyboardist will play the tuning note if he or she is the soloist for the evening.
The purpose of a tuning fork is to know the exact pitch of a certain note, and then tune to that note. The string is probably loosened to match the pitch of the tuning fork.
Tuning forks are available for all standard notes, but the most common is an A note, which is 440 Hz
The standard tuning note for the high E string on a guitar is E.
A440, also known as the A above "middle C", and further known as the note most commonly associated with 440 hertz was made the international standard for pitch decided upon in 1955 (ISO 16), and was reaffirmed by the same organization in 1975. http://en.wikipedia.org/wiki/Pitch_(music) I can't find any reasoning as to why A has always traditionally been used for the pitch standard. Even when the tuning fork was originally invented, an A was chosen as the best tuning note. My best guess is that it is due to the note's alphabetic significance. It should also be noted that although some orchestras tune to an electronic tone that is calibrated to 440 hertz, many do not. Many orchestras are primarily concerned with whether or not they're in tune with each other, and as such, the entire orchestra (or band) often tune to an oboe. The oboe cannot change its tuning, so oftentimes the other members of the band tune to it. One of the primary reasons for an orchestra, or any group for that matter, to tune to A440 is when there is an instrument whose tuning cannot easily be changed, such as a piano, or organ with a fixed tuning to A440.
In most modern western music, the standard tuning note is A 440, meaning 440 hz (440 cycles per second). The most common deviation from this is found in Baroque music, where the tuning note is usually A 415, which is slightly lower in pitch.
Orchestras are usually tuned to an oboe. The open note, (that is, the note an oboe plays without any fingering), is an A, and the orchestra tunes best to that note. When a piano is featured as solo instrument, the orchestra tunes to the A of the piano, because it's easier for them to adjust their pitch than for the piano.
The frequency of a 440 Hz note in music is the pitch commonly used as the reference point for tuning instruments. It is known as the standard tuning pitch, meaning that most instruments are tuned so that the A above middle C corresponds to a frequency of 440 Hz.
Depending on how you are learning1, 2, 3, and 4G'CEA
The most standardize tuning for guitars both acoustic and electric is EADGBe(the lower note indicating this is the highest) with the A being at 440hz. This is only standard tuning and you can tune your guitar several different ways depending on what kind of music you are playing. My favorite open-tuning(tuning your strings to the note of an open chord such as G, Em, etc) is Em which is EBEGBe or E Maj which is EBEG#Be. For a fuller list of tunings, see trealted link.