In DnD intelligence is directly proportional to your knowledge base. Every skill barring Investigation is a check to see if you know a fact or not. So intelligence in the context that we're discussing is basically your knowledge stat.
No, that is skills or proficiencies depending on what edition you are playing. To quote the 3.5e player's guide -since I don't recall where I saved the 5e one:
INTELLIGENCE (INT)
Intelligence determines how well your character learns and reasons.
This ability is important for wizards because it affects how many
spells they can cast, how hard their spells are to resist, and how
powerful their spells can be. It’s also important for any character
who wants to have a wide assortment of skills.
WISDOM (WIS)
Wisdom describes a character’s willpower, common sense, perception,
and intuition. While Intelligence represents one’s ability to
analyze information, Wisdom represents being in tune with and
aware of one’s surroundings. An “absentminded professor” has low
Wisdom and high Intelligence. A simpleton (low Intelligence)
might still have great insight (high Wisdom). Wisdom is the most
important ability for clerics and druids, and it is also important for
paladins and rangers. If you want your character to have acute
senses, put a high score in Wisdom. Every creature has a Wisdom
score.
For example, using that version since I have it on hand and am much more intimately knowledgeable on it - a character with an 18 intelligence score may know a whole lot about knowledge (medicine) and knowledge (the planes) but clearly have to defer to an intelligence 6 character on knowledge (history) because they didn't invest in that knowledge. Intelligence has a potential toward knowledge, but it doesn't necessarily apply. In fact, you can have a character with high intelligence with no specialized knowledge at all if they put all their skill points into jumping, hiding, moving silently, and such. Or, to use 5e, if their proficiencies are all in charisma and physical things. I have a few skill levels invested in knowledge (3.5e) but someone less intelligent than myself may very well be proficient with knowledge (5e).
