One verb at a time
Morir ‘Morir’ means ‘to die’ and there is not a great deal more one can say about the meaning. It is a root-changing verb, so the letter ‘o’ in the root changes to ‘ue’ in certain forms in the present tense.
For obvious reasons, and when used literally, this verb is mostly used on the third person, so ‘he or she dies’ is ‘muere’ and ‘they die’ is ‘mueren’.
It has a small variation of form in the preterite or past simple tense, also in the third person where the ‘o’ changes to ‘u’ so ‘he or she died’ is ‘murió’ and ‘they died’ is ‘murieron’.
This verb has a couple more irregularities, firstly the present participle, or gerund, makes the same ‘o’ to ‘u’ change, so that ‘dying’ is ‘muriendo’ and finally the past participle, that is ‘died’ in the context of ‘has/have died’ is ‘muerto’.
The one phrase that always jumps into my mind regarding this last word is the announcement made on television by the then president of the Spanish government at the death of Franco "Españoles, Franco ha muerto" (Spaniards, or people of Spain, Franco has died).
This past participle is probably very recognisable to you as it has another very common usage, that is as the adjective ‘dead’.
With this meaning the word is usually accompanied by the verb ‘estar’ ‘Mi padre está muerto’
(My father is dead) and also, being an adjective it’s ending can have four changes to agree with masculine, feminine, singular and plural (muerto, muerta, muertos, muertas).
As in English, we can also use the verb ‘to die’ in a figurative sense, for example ‘I died of embarrassment’ or ‘I nearly died when he told me that’.
Spanish deals with this by making the verb reflexive ‘morirse’.
‘Morirse de vergüenza’ means ‘to die of embarrassment’, ‘Cuando vi la foto me morí de vergüenza’
(When I saw the photo I died of embarrassment). Sometimes when someone is laughing a lot they might exclaim ‘¡Me muero!’
(I’m dying!). Remember in English we talk about ‘killing ourselves laughing’. We can also say ‘nos morimos de hambre’ (we’re dying of hunger) or ‘se muere por ir al concierto’ (He’s dying to go to the concert).
Other words that are derivative of ‘morir’ are ‘moribundo’
(moribund, dying or almost dead) and one of the words for mortuary is ‘mortuorio’ although it is more usual in Spain to use the word ‘morgue’ for mortuary and ‘tanatorio’ for what we rather prissily call a ‘funeral parlour’.
It is interesting to note once more that formal vocabulary in English comes from Latin and is therefore more similar to Spanish, whereas ‘dead’ is a straightforward Anglo-Saxon word of Germanic origin.
Finally, on this rather dismal subject, sometimes people want a softer word than ‘morir’ to express their loss, and whilst Spanish is a more direct language in general,
there is a synonym ‘fallecer’ which has a slightly gentler sound.
‘Mi marido ha fallecido’ (My husband has passed away).