The jargon, in one sentence each

Congress publishes its record in its own language, and this site shows that record unedited — paraphrasing it would defeat the point. So the terminology stays and the explanation sits next to it. Anywhere you see a dotted underline on the site, tapping it gives you the sentence below.

Kinds of vote

Most recorded votes in Congress are not votes on a bill. They are votes about whether to vote, and they are where most legislation actually dies.

Cloture: A vote to end debate in the Senate so a final vote can happen — it needs 60 senators, which is why so many bills die without ever being voted on.
Motion to proceed: A vote on whether the Senate will even start debating something. Losing it kills the bill without anyone having to vote on the bill itself.
Suspension of the rules: A fast track in the House: no amendments, forty minutes of debate, and a two-thirds majority needed to pass — used for bills expected to be uncontroversial.
Motion to recommit: The minority party's last chance to change a bill before the final vote, by sending it back to committee. It almost always fails, and it's mostly used to force the majority into an awkward recorded vote.
Ordering the previous question: A procedural vote to cut off debate and amendments in the House. It sounds neutral and isn't — it's usually a party-line vote about who controls what happens next.
Motion to table: A vote to kill something without debating it. A yes vote here is a vote against whatever is being tabled.
Motion to concur: A vote on whether to accept the changes the other chamber made. This is often the vote that finally settles a bill.
On passage: The vote on whether the bill itself passes — the one most people mean by “the vote”.
Voice vote: Members shout aye or no and the chair decides which was louder. Nobody's individual vote is recorded, so there's nothing to hold anyone to.
Unanimous consent: Passing something by nobody objecting, rather than by voting. It takes one senator to stop it, and no one's position is recorded.
Present: A recorded decision not to take a side — different from missing the vote, and usually deliberate.
Not voting: No vote was recorded for that member — they were absent, or chose not to appear.
Amendment to the title: A formal vote to rename a bill — which usually means its contents changed enough that the old name no longer described it.
Approving the Journal: A routine vote approving the previous day's official record. It decides nothing, and is mostly used to check who's in the building and who votes with their party.
On the nomination: A Senate vote to confirm somebody the President has appointed — a judge, an ambassador, a cabinet secretary. Not legislation.
Conference report: The single compromise text agreed by negotiators from both chambers. It can't be amended — the vote is take it or leave it.
Veto override: A vote to pass a bill the President rejected. It needs two thirds of both chambers, which is why it almost never succeeds.

Where a bill is

The stations a bill passes through, and what each one really means.

Referred to committee: Sent to the committee that handles that subject. This is where the overwhelming majority of bills stop, permanently, without a vote.
Markup: The meeting where a committee goes through a bill line by line and changes it.
Reported: The committee has finished with it and sent it to the full chamber. “Reported (Amended)” means they changed it first.
Placed on the calendar: Queued for possible floor time. It is not a schedule — most bills on the calendar are never called up.
Engrossed: The official final text as one chamber passed it, sent to the other chamber.
Enrolled: The final text agreed by both chambers, on its way to the President's desk.
Became public law: Signed by the President, or passed over a veto. It is now law.
Amendment in the nature of a substitute: An amendment that replaces the entire text of a bill. Routine at committee stage; when it happens after a bill has already passed a chamber, the bill can become something else entirely.
Legislative vehicle: A bill kept alive for its number rather than its contents — its text is struck out and replaced with unrelated legislation, often to satisfy a constitutional rule or to skip a procedural step.

Kinds of measure

Not everything Congress votes on is a bill, and several of these never become law however many people vote for them.

Simple resolution: H.Res. or S.Res. — a measure affecting only the chamber that passes it. It doesn't go to the other chamber and it doesn't become law.
Concurrent resolution: H.Con.Res. or S.Con.Res. — passed by both chambers but never signed by the President, so it doesn't have the force of law. Budget targets and formal expressions of opinion use these.
Joint resolution: H.J.Res. or S.J.Res. — legally the same as a bill and signed the same way. Used for constitutional amendments and for overturning federal regulations.
CRS summary: A plain-English description of a bill written by the Congressional Research Service, Congress's own non-partisan analysts. They write one per major action, and often only ever write the first.
Cosponsor: A member who formally adds their name to somebody else's bill. It's dated, official and public — which is what makes it something they can be held to.

Money

The categories campaign finance data comes in.

PAC: A political action committee — an organization that collects money and gives it to candidates. Most corporate and union giving reaches politicians this way.
Outside spending: Money spent supporting or attacking a candidate without going through their campaign. It is not limited, and the campaign is not allowed to coordinate it.
Lobbying disclosure: A quarterly filing in which registered lobbyists must list the issues and often the specific bills they worked on. Most say only that they “monitored” something.

Ours

Terms this site made up, which therefore need explaining most of all.

Decisive vote: The roll call that actually settled a bill, picked from the dozen procedural votes it may have generated. Every score on this site uses it, so the same vote is being compared everywhere.
The Needle: Your voting record placed between the two parties, counting only bills where the parties actually disagreed. It's private unless you publish it.