Tilde sign ~

This IS genealogical!
I'm just going back over old notes and letters, and found one where a
correspondent has written along the lines of : "he was born ~1825".

Now, I'm assuming that in this context it means "more or less" or
"estimated", but I don't really know. My daughter has A-level maths books,
but the explanation there is no help in the context.

squealing...

From a methematician's perspective, "~" means "approximately", or
"equivalent to" and applies to any type of number. In the context of record
keeping of dates, I suggest it is less ambiguous to use "About" or "Circa"
(Note: circa applies exclusively to dates, thus technically it means
something different to ~).

Tip: "About" dates can be preserved in GED files, so if you share your
research files with others you will preserve the idea of it being an
approximation. Similarly you can use "Before" with a date when recording
births and all you have to go on is a baptism.

Depending on the family history program you use to keep your records, you
may find you already have a good setting for this - try prefixing the next
date you enter with "about" next time.

In my version of Family Tree Maker you can tweak the words it uses under
File>Preferences>Dates&Measures

Joe Makowiec...

You're quite correct.

Steve Hayes...

That was useful.

I always wondered what those URLs with a tilde in meant.

It also causes problems, because my word processor uses tilde for a soft
hyphen, so when I edit something with web addresses, I have to be careful that
they stay visible.

Anybody with firm knowledge of usage? (not VERY important, but it's always
nice to know)

Allen...

Another reason to spell out what you mean. Why not write "about",
"around", "near", "circa", even "approximately". I have totally
discontinued using any abbreviations in my genealogical work. US state
names or great examples of the confusion that abbreviations can lead to,
especially when there is a history of their changing over time. Fifty
years from now will a reader know which state "MN" refers to--Montana?
Maine? Minnesota? Or MO--Missouri? Montana?