The Greek kalamē refers to the stalk of grain after the head has been cut off — straw or stubble. It represents what remains after harvest: dry, worthless material easily burned.
Paul uses kalamē (straw/stubble) in 1 Corinthians 3:12 as one of the materials that builders may use in constructing on the foundation of Jesus Christ. The Day of Judgment will test each person's work with fire — 'if it is burned up, the builder will suffer loss but yet will be saved.' Straw and stubble are flammable: they produce impressive-looking structure quickly but cannot withstand the fire of divine scrutiny. The image warns against ministry built on impressive techniques, cultural accommodation, or crowd-pleasing approaches that will not endure. The contrast is with gold, silver, and precious stones — work built through costly, enduring, Spirit-led faithfulness. The eschatological fire reveals the quality, not just the quantity, of what we have built.