Federal Contracting Acronym
SLIN
Subline Item Number
Plain-English definition
Subline Item Numbers (SLINs) break out elements under a Contract Line Item Number—options, funding lines, deliverables, or separately priced features. SLINs appear on awards, modifications, and invoicing systems so finance and program offices can track obligations at a finer grain than the parent CLIN. Proposal teams mirror SLIN structure in pricing volumes to avoid mapping errors at award.
Why it matters
Misaligned SLIN pricing or missing option SLINs cause modification delays and payment holds on exercised options.
Where you will see it
Award documents, SF 1449 schedules, WAWF invoices, and CDRL/deliverable tables tied to specific SLINs.
Example in context
A contractor prices Base CLIN 0001 with SLIN 0001AA for Phase 1 labor and SLIN 0001AB for travel, matching the government's UCA structure.