feat: Initial commit.

Definitions.md

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+# Definitions
+
+<!-- NOTE: Keep these at the very bottom, if any new definitions are added then
+           they should also be added as links to the content section near the top. -->
+
+### IAQ {#iaq-definition}
+
+Stands for $I$ndoor $A$ir $Q$uality. We spend most of our time indoors, so having good indoor air
+quality can help reduce illness and potentially improve the quality and longevity of life.
+
+### TESP {#tesp-definition}
+
+Stands for $T$otal $E$xternal $S$tatic $P$ressure, which is a metric used to determine how much
+resistance the blower motor has to overcome for the airflow requirement of the system.
+
+### WC {#wc-definition}
+
+Stands for $W$ater $C$olumn, which is a unit of measurement for pressure.