diff --git a/content/notes/terminology.md b/content/notes/terminology.md
index a9458c81a..e5b516adc 100644
--- a/content/notes/terminology.md
+++ b/content/notes/terminology.md
@@ -9,4 +9,6 @@ tags:
 **column space:** the set of all possible outputs Av is the column space of A
 **full rank:** When the rank equals the number of columns
 **null space/kernel:** the space of all vectors that become null following a transformation
- **span:** 
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+ **span:** a set of all linear combination of two vectors
+ **linear combination:** an expression constructed from a set of terms by multiplying each term by a constant and adding the results
+ 
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