electronic cigarettes - overarching term that includes vapes, hookah pens, or JUULs; e-cigarettes are inhaled and produce an aerosol cloud of a certain substance (nicotine, marijuana, etc.).
JUULs - a type of e-cigarette resembling a USB that contains nicotine and comes in different flavors (mango, mint, creme brulee)
vapes - another type of e-cigarette that comes in different forms (vape pens, personal vaporizers, etc.) and contains various chemicals but not tobacco; the JUUL is a type of vaping product
Are there any other relevant and important definitions that we must know in order to initiate this discussion?