Anthem doesn't explain a lot of things, and it's confusing when equipping abilities and weapons to understand what both symbols on Inscriptions actually mean. 

Global - Javelin

Some Inscriptions directly affect your entire Javelin, and this includes all your abilities and items. When you see a Javelin symbol next to an Inscription, the bonuses provided directly boost everything available to you.

Item - Gear

A gear icon, or cog, affects only the item or ability you're wielding. If that's a weapon or ability, any benefit is directly linked to that, not the rest of your kit. 

Example

In this image, the Papa Pump (Masterwork Shotgun) has 4 Inscriptions:

• (Javelin) Q +20% Speed
• (Javelin) Repair +5% Amount
• (Javelin) A-Rifle +17% Ammo
• (Gear) Weapon -35% Recoil Aim

The gear icon is related directly to this weapons recoild, and decreases it by 35%. In constrast, the three other Inscriptions all affect the Javelin and the rest of its kit. The 20% speed bonus and the Assault Rifle +17% ammo would also affect other weapons, and your ability.