IRS vocabulary
Tax resolution glossary
The acronyms, form numbers, and IRS jargon you'll hear during a tax resolution case — defined in plain English so you can follow what's actually happening.
- Terms defined
- 18
- Format
- Plain English
- Updated
- 2025
The IRS speaks its own language — CSED, CNC, OIC, TFRP, CDP. When you're in collections, every one of these acronyms maps to a deadline or a dollar figure. This glossary defines 18 terms in plain English so you can read your notices, follow your case, and ask sharper questions.
Tip: every term has a permalink — share a definition by clicking the term name.
A
- Automated Collection System (ACS)
- The IRS call-center collection function that handles taxpayer accounts not assigned to a field Revenue Officer.
B
- Bank Levy
- An IRS legal seizure of funds in a taxpayer's bank account. Banks must hold the funds for 21 days before remitting them to the IRS.
C
- Collection Due Process (CDP) Hearing
- A hearing before the IRS Office of Appeals triggered by a Final Notice of Intent to Levy or a Notice of Federal Tax Lien Filing. CDP hearings stop active collection while pending.
- Collection Statute Expiration Date (CSED)
- The date IRS authority to collect a tax debt expires — generally 10 years from assessment, subject to tolling events.
- Currently Not Collectible (CNC) / Status 53
- IRS designation that places a taxpayer's account on collection hold due to financial hardship.
F
- Federal Tax Lien
- The federal government's legal claim against a taxpayer's property arising from unpaid tax debt.
I
- Installment Agreement (IA)
- An IRS-approved monthly payment plan for satisfying outstanding tax liability.
L
- Levy
- The actual seizure of property by the IRS to satisfy tax debt — distinct from a lien, which is a claim.
N
- Notice of Deficiency (90-Day Letter)
- Statutory notice that gives a taxpayer 90 days to petition the U.S. Tax Court before tax is assessed.
O
- Offer in Compromise (OIC)
- An agreement that settles a taxpayer's IRS liability for less than the full amount owed.
P
- Partial Pay Installment Agreement (PPIA)
- An installment agreement that won't fully pay the balance before the CSED expires.
- Power of Attorney (Form 2848)
- Form authorizing a credentialed representative to act on a taxpayer's behalf before the IRS.
R
- Reasonable Cause
- A standard for penalty abatement based on circumstances beyond the taxpayer's control.
- Revenue Officer (RO)
- An IRS field collection employee assigned to higher-priority or more complex collection cases.
S
- Statute of Limitations
- The legal time limit for IRS action — 3 years for assessment (generally), 10 years for collection.
- Substitute for Return (SFR)
- A return filed by the IRS on behalf of a non-filer, typically calculating tax without deductions, which results in an inflated balance.
T
- Trust Fund Recovery Penalty (TFRP)
- Personal assessment of unpaid trust-fund employment taxes against responsible individuals.
W
- Wage Garnishment / Wage Levy
- An IRS levy on a taxpayer's wages, requiring an employer to send a portion of each paycheck to the IRS.
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