A *(programming language). From its home page (see below):
<blockquote>
Hume (<strong>H</strong>igher-order <strong>U</strong>nified <strong>M</strong>eta-<strong>E</strong>nvironment) is a _(strongly typed|Type System), mostly-*(functional) language with an integrated tool set for developing, proving and assessing _(concurrent), safety-critical systems. Hume aims to extend the frontiers of language design for resource-limited systems, including real-time embedded and safety-critical systems, by introducing new levels of _(abstraction) and provability.
</blockquote>

<ul class="implementations">
<li>_("The Hume Page"|http://www.hume-lang.org/)
</ul>
