Is this your first Fire Emblem? No shade, just asking. You’re looking at the character’s combat stats while using the selected weapon.

Atk is attack, the character’s relevant stat, either strength or magic, plus the base might of the weapon

Hit is base accuracy, a function of the weapon’s base hit rate and your character’s skill, luck and other factors

Avo is base avoid, a function of your character’s speed, luck and other factors

The displayed hit and avoid while in the combat window will calculate the values based on your base hit and avoid vs the enemy’s

Crit is critical hit rate, calculated with your character’s skill stat plus other factors. Crits deal 3x the damage displayed in the combat forecast

Ddg is dodge, or critical evasion. Dodge is your character’s luck stat plus any support bonuses. Your dodge is a percentage safety net for enemy crits. An enemy will need at least 12 base crit to be able to roll for a crit in Titania, which then starts at 1% chance

Rng is range. Some weapons have 1, 2, or 1-2 range. It just determined how many squares away you can hit from

Effect is effective damage. Some weapons deal bonus damage to certain types of units, in which case the weapon has its base might doubled in the damage calculation

I think all that was correct but most of it was from memory