I have a LaTeX document written with normal English quotes, eg.:

```
``This is a quoted text.''

```

Now, I would like to redefine ```` and `''`, so the *combination* of two ``` characters is substituted with, say, `<` and `>`. The result should be as if I had written:

```
<This is a quoted text.>

```

I find that I miss the Latex vocabulary for describing and searching for the issue. What is ```` at all? A two glyph character? A command? A macro? What is its relation to ```?