What does "fortunately" mean?

1. (luckily) used to say that something good happened or that a situation is lucky. 2. (in a lucky way) in a way that shows good luck or success.

Is it correct to say "Fortunately, we didn't lost the keys."?

No — say "Fortunately, we didn't lose the keys.". Remember that 'didn't' is followed by the base form of the verb, even when the sentence starts with 'fortunately'.

fortunately

adv.

US //ˈfɔɹtʃənətɫi// UK //fˈɔːtʃənətli// for·tu·nate·ly

1 luckily (adv.)
A2 Elementary

used to say that something good happened or that a situation is lucky.

used as a sentence modifier to express that the situation described is fortunate or lucky.

Example

I forgot my umbrella, but fortunately, it didn't rain while I was walking.

Example

Fortunately, the emergency services arrived within minutes of the call, preventing the fire from spreading to the adjacent buildings.
- luckily
- happily
- unfortunately
- unluckily
Pitfall

Fortunately, we didn't lost the keys.

Fortunately, we didn't lose the keys.

Remember that 'didn't' is followed by the base form of the verb, even when the sentence starts with 'fortunately'.
2 in a lucky way (adv.)
B2 Upper Intermediate

in a way that shows good luck or success.

in a fortunate or auspicious manner; modifying a specific action rather than the whole sentence.

Example

The business was fortunately placed to benefit from the new laws.

Example

The company was fortunately positioned within the market, allowing it to expand rapidly during the economic recovery.
- luckily
- successfully
- unluckily

Origin

From fortunate + -ly.

Word family

Adjectivefortunate
Adverbfortunately
Adverbunfortunately