A tilde in front of a single quantity can mean approximately, about or of the same order of magnitude as.. In written mathematical logic, the tilde represents negation : ~ p  means not p , where  p  is a proposition.
https://en.wikipedia.org/wiki/Tilde
1. tiddler-a young person of either sex; she writes books for children; they're just kids; `tiddler' is a British term for youngster. child, kid, minor, nipper, youngster, shaver, small fry, tike, nestling, fry, tyke. child's body-the body of a human child.
http://www.thefreedictionary.com/Tiddle
Origin. The phrase 'jot or tittle' is somewhat tautological, as both jot and tittle refer to tiny quantities. It has passed into English via William Tindale's translation of the New Testament in 1526.
http://www.phrases.org.uk/meanings/jot-or-tittle.html
In phonetics, a tilde is used as a diacritic either placed above a letter, below it or superimposed onto the middle of it (see International Phonetic Alphabet → Diacritics): 1  A tilde above a letter indicates nasalization, e.g. [a], [ã] .  ṽ
https://en.wikipedia.org/wiki/Tilde
tiddler. n. 1. (Animals) a very small fish or aquatic creature, esp a stickleback, minnow, or tadpole. 2. a small child, esp one undersized for its age.
http://www.thefreedictionary.com/Tiddle
For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled. A jot is the name of the least letter of an alphabet or the smallest part of a piece of writing. It is the Anglicized version of the Greek iota-the smallest letter of the Greek alphabet, which corresponds to the Roman 'i'.
http://www.phrases.org.uk/meanings/jot-or-tittle.html
Noun. 1. piddle-liquid excretory product; there was blood in his urine; the child had to make water. pee, piss, urine, weewee, water. body waste, excrement, excreta, excretory product, excretion-waste matter (as urine or sweat but especially feces) discharged from the body.
http://www.thefreedictionary.com/piddle
Hence, when we have a brief note to make, we 'jot it down'. A tittle, rather appropriately for a word which sounds like a combination of tiny and little, is smaller still. It refers to a small stroke or point in writing or printing.
http://www.phrases.org.uk/meanings/jot-or-tittle.html
The tilde has since been applied to a number of other uses as a diacritic mark or a character in its own right. These are encoded in Unicode at U+0303 ◌̃ combining tilde and U+007E ~ tilde (as a spacing character), and there are additional similar characters for different roles.
https://en.wikipedia.org/wiki/Tilde
The tilde (/ˈtɪldə/ ; ˜ or ~) is a grapheme with several uses. The name of the character came into English from Spanish, which in turn came from the Latin titulus, meaning title or superscription.
https://en.wikipedia.org/wiki/Tilde
what is a tiddle?
A tiddle is a young person of either sex.