A house habitually kept open to callers. / An event, often in one's home, at which there are few restrictions regarding who and how many may attend.

A UK university offering distance learning taught courses to people without formal academic qualifications, teaching being by correspondence and online with mostly optional tutorials and for some courses compulsory summer schools. Access to postgraduate research is selective and is primarily taught on campus using traditional methods.

A mind willing to consider new ideas.

A device used to remove the cap from a bottle / A device used to remove the cork from a bottle

(software) The practice of providing open-source code for a product. / (software) Open-source software in general. / (espionage) Information that is in the public domain and available to everybody.

Frank and candidly straightforward / Generous and kind / Emotionally receptive

completely open / having no laws or law enforcement / unsettled or unresolved / vulnerable or unprotected / (sports) without the presence of opponents nearby

(computing) A system allowing hardware and software from different manufacturers to be used together seamlessly. / (physics) A system that can exchange both matter and energy with its surroundings.

A knifelike device with a blunt edge, used for slicing letters open.

The credits shown at the beginning of a film, TV program, etc.