Valve has filed a trademark application for Half-Life 3.
The trademark application (via NeoGAF) was filed September 29 with the European Union's Office of Harmonization for the Internal Market (OHIM).
It covers "computer game software; electronic game software, downloadable game software via a global computer network and wireless devices; and video game software," among other things.
A Valve representative was not immediately available to comment regarding what this news may mean for the future of Half-Life. A trademark application does not necessarily indicate that Half-Life 3 is in development.
Last week, Valve announced SteamOS, Steam Machines, and a Steam Controller. The announcements did not win everyone over, as Gearbox Software CEO Randy Pitchford said Valve needs to introduce a killer app to display why the new initiatives are compelling. He specifically said a product like Half-Life 3 would accomplish this.
In August, Half-Life series voice actor John Patrick Lowrie said Half-Life 3 is not in development, though he admitted he has "no idea" what Valve may be planning in the future.
Last April, Valve boss Gabe Newell said the studio had gone through numerous "twists and turns" to bring Half-Life 3 to market. He explained that Valve's silence is in the best interest of gamers because elaborating on the game's development "would probably drive people more crazy."
The most recent Half-Life game was 2007's Half-Life 2: Episode Two. That game advances the story of previous entries Half-Life 2 and Half-Life 2: Episode One. A third episode was planned, but has not seen the light of day.
A listing for Half-Life 3 was recently spotted in a Valve project tracker.