Square root is the root of a square (number multiplied with itself),
here the english language is very literally.
The squara root of 2 is length of the diagonal within a unit square.
It can be also considered the key of the 1.5th dimension.
1 . 4 1 4 2 1 3 5 6 2 3 7 3 0 9 5 0 4 8 8 0 1 6 ...
1.4142135623 7309504880 1688724209 6980785696 7187537694
8073176679 7379907324 7846210703 8850387534 3276415727
3501384623 0912297024 9248360558 5073721264 4121497099
9358314132 2266592750 5592755799 9505011527 8206057147
0109559971 6059702745 3459686201 4728517418 6408891986
0955232923 0484308714 3214508397 6260362799 5251407989
6872533965 4633180882 9640620615 2583523950 5474575028
7759961729 8355752203 3753185701 1354374603 4084988471
6038689997 0699004815 0305440277 9031645424 7823068492
9369186215 8057846311 1596668713 0130156185 6898723723
5288509264 8612494977 1542183342 0428568606 0146824720
7714358548 7415565706 9677653720 2264854470 1585880162
0758474922 6572260020 8558446652 1458398893 9443709265
9180031138 8246468157 0826301005 9485870400 3186480342
1948972782 9064104507 2636881313 7398552561 1732204024
5091227700 2269411275 7362728049 5738108967 5040183698
6836845072 5799364729 0607629969 4138047565 4823728997
1803268024 7442062926 9124859052 1810044598 4215059112
0249441341 7285314781 0580360337 1077309182 8693147101
...
is the square root of 2 with 950 digits.
The first 1,000,000 digits of sqrt 2 (1.1MB),
taken from the Gutenberg Project.
The newton's formula (which is assumed the babylonians used already) to calculate the square root of b:
xnew = 1/2 * ( x + b/x )
used as appromixation, after 6-10 cycles you get a very good approximation of the
square root.