Definition
A cost incurred or amount paid out in connection with some purpose, activity, or obligation. In legal contexts, "expense" most often appears in one of three distinct settings:
1. Litigation costs. Amounts disbursed in connection with pursuing or defending a legal proceeding. May overlap with, but is not always identical to, the technical category of "costs" taxable to a losing party. "Expenses of litigation" typically includes the broader universe of outlays — attorney's fees, expert witness fees, travel, copying — while court-taxable "costs" are a defined subset.
2. Business and tax law. An expenditure incurred in the ordinary course of trade, business, or income-producing activity. In tax law, the term carries particular weight: an "expense" is a currently deductible outlay, as distinguished from a "capital expenditure," which must be recovered over time through depreciation or amortization. Whether an outlay is an expense or a capital expenditure is one of the most litigated questions in federal tax law.
3. Estate and trust administration. Charges incurred in administering an estate or trust, including funeral expenses, costs of probate, and ongoing management costs. Allocation of expenses between income and principal beneficiaries is governed by trust accounting rules and, in many states, the Uniform Principal and Income Act.
Common Language
Modern common usage (Wiktionary): A spending or consuming, often a disbursement of funds; the elimination or consumption of something, sometimes with the notion of loss or damage.
Historical common usage (Webster's 1913): "That which is expended, laid out, or consumed; cost; outlay; charge — sometimes with the notion of loss or damage to those on whom the expense falls."
The common meaning and legal meaning align closely in ordinary usage, but legal practice layers on critical distinctions the common meaning ignores entirely. Most importantly, tax law draws a hard line between an "expense" (deductible now) and a "capital expenditure" (not deductible now), a distinction with no counterpart in everyday speech. Similarly, in litigation, "expenses" and "costs" are colloquially interchangeable but are legally distinct categories with different recoverability rules.
Common Confusion
Expense vs. cost (litigation context): In ordinary speech these are synonyms. In procedure and fee-shifting law, "costs" refers to a specific, often statutorily defined category of recoverable amounts (filing fees, transcript fees, and similar items), while "expenses" is broader and may or may not be recoverable depending on the governing rule or agreement. A prevailing party awarded "costs" does not automatically recover all litigation expenses.
Expense vs. capital expenditure (tax context): The distinction is fundamental. An expense is currently deductible; a capital expenditure must be capitalized and recovered over the asset's useful life. The line between them turns on whether the outlay produces a benefit extending substantially beyond the current tax year. Section 179 of the Internal Revenue Code allows certain capital expenditures to be "expensed" — treated as currently deductible — which underscores that "expensing" in tax law is a term of art meaning the election to treat what would otherwise be a capital outlay as a current deduction.
Why It Matters in Research
The word "expense" is deceptively uniform across legal sources but means materially different things depending on context. A researcher working across litigation, tax, and estate sources must resist treating the term as consistent.
In historical sources, "expense" and "costs" are used interchangeably more often than modern practice permits. Burrill's civil-law entry — drawing on the Corpus Juris Civilis formula that the vanquished party shall be condemned in costs ("victus victori in expensis condemnabitur") — reflects a tradition where expense and cost of suit were synonymous. Modern procedural law has since bifurcated these, and reading historical sources without that awareness will distort the analysis.
In the tax corpus, the expense/capital expenditure distinction is the central recurring problem. The Law Mind Tax Encyclopedia entries on trade or business expenses and Section 179 expensing address the modern statutory and regulatory framework. Researchers should be alert to the fact that what "expense" means under the tax code is a product of intensive regulatory and judicial elaboration; the plain word gives almost no guidance on its own.
In estate and trust contexts, "expenses" appears in allocation disputes between income and remainder beneficiaries. The answer turns not on the word itself but on the applicable trust instrument, state statute, and accounting conventions.
Historical Dictionary Support
Burrill grounds the term in the civil law, where "expensæ" or "expensæ litis" referred to costs of suit — the charges incurred in litigation, recoverable by the prevailing party. The maxim "victus victori in expensis condemnabitur" (the vanquished party shall be condemned to the victor in costs) captures the civil-law baseline: cost-shifting to the loser was the default rule, a posture very different from the American Rule, which generally requires each party to bear its own litigation expenses absent a fee-shifting statute or agreement.
Burrill also notes the civil-law usage of "funus" — funeral expenses — as a distinct legal category, reflecting the ancient recognition that certain outlays arising from death hold special status in the administration of an estate.
Webster's 1913 captures the ordinary English sense accurately but, as noted above, does not engage with the legal distinctions that make the term significant in practice. Historical legal dictionaries generally treat "expense" as unremarkable vocabulary, which itself signals that the term's legal complexity is largely a modern development driven by tax law and procedural codes.
Jurisdictional Note
In federal tax law, the expense/capital expenditure distinction is governed by the Internal Revenue Code and Treasury regulations, with a substantial body of case law defining the boundary. State tax regimes vary in their conformity to federal definitions. In litigation cost recovery, state procedural rules differ significantly from federal rules and from each other in defining what qualifies as a taxable "cost" versus a broader recoverable "expense."
Encyclopedia Cross-Reference
Section 179 Expensing (The Law Mind Tax Encyclopedia)
Deductions — Trade or Business Expenses (The Law Mind Tax Encyclopedia)
Deductions — Educator Expenses (The Law Mind Tax Encyclopedia)