There is a lot to know about the particle と. However, this lesson will only focus on the case particle と. If you don't quite remember what a case particle is, don't worry. These particles simply show basic grammatical relationships in a sentence.
Noun＋と＋Noun(と）
と's basic meaning is "and" when placed in between nominal phrases. If you want to use something else, it has to become a noun first. と can't be used at the beginning of a sentence. In that case, you should use something like そして. When listing more than two things, consecutive と may be omitted, and this is usually the most natural thing to do. と is typically not used after the last item, but it can be in older language.
1a. 私は日本人と医者です X
1b. 私は日本人で医者です。 〇
I am Japanese and a doctor.
Grammar Note: Again, this meaning is for when と is between two or more nouns! 1a is wrong because this rule is violated in a more complicated way. In English "I am Japanese and a doctor" is technically short for "I am Japanese and I am a doctor." Here it is clear that you are actually connecting two predicate phrases, not two simple noun phrases. If you wanted to say that "X and Y are doctors," you would use と.
2a. すばしっこいと茶色の狐はのろまな犬を飛び越える。 X
2b. すばしっこい茶色の狐はのろまな犬を飛び越える。〇
The quick brown fox jumps over the lazy dog.
Example Note: 2b is grammatically correct, but because it is a translation of a sentence in English that has each letter of the alphabet in it, the Japanese sounds somewhat like a direct translation. For instance, this sentence has an unnecessarily lengthy subject. In Japanese, such lengthy subjects tend to sound unnatural.
Examples
3. リンゴとブドウがテーブルの上にあります。
There are apples and grapes on the table.
4. これとそれは同じです。
This and that are the same.
5. ノートと教科書と辞書を持ってきてください。
Please come with your notes, textbook, and dictionary.
6. 犬と猫がいる。
I have a dog and a cat; there is a dog and a cat.
7. 犬と猫を飼っている。
I have a dog and a cat.
8. 日本語のクラスにはアメリカ人と、イギリス人と、カナダ人がいます。
There are Americans, English, and Canadians in (my) Japanese class.
9. 朝と夜はちょっと寒いです。
Morning and night are a little cold.
Particle Note: This pattern used to be XとY（と） for "X and Y." If you ever see something like XとYとが, you're not seeing a typo. It's just not frequently used.
With
と may show the partner in which a person of interest is doing an action with. Both the "and" and "with" definitions can be in the same sentence as they're not the same and have different requirements. The word after と when it means "with" is not part of the same phrase as と.
10. ｛両親・父と母｝と公園に行きます。
I'm going to the park with my father and mother.
11a. 犬と散歩に出かけた。
11b. 犬の散歩に出かけた。
I went out on a walk with my dog.
Nuance Note: Both 11a and 11b are grammatical, but 11a sounds as if you are elevating the dog to the same level of importance as yourself whereas 11b means that you are simply taking the dog out for its walk.
と一緒に and と共に both may mean "together" or "jointly". と一緒に is only used with two compatible nouns that are same in status and kind. You can't use it in "I talked together with my teacher". ご一緒する is honorific but means "to go with". とともに is more formal and shows that things/people are doing something or in the same state together.
12. 彼女と彼は結婚する。 (Don't need 一緒に)13. 宏と花子は同時に結婚する。
Hiroshi and Hanako will marry simultaneously.
14. 彼らは一緒に敵と戦っていた。
They fought the enemy together.
15. 彼らは敵と一緒に戦っていた。
They fought mutually with the enemy.
16. あたしは日の出とともに起きます。（Feminine)
I rise with the sun.
17. 夫婦ともに元気です。
The husband and wife are both fine.
18a. 誰かと悲しみを共にすることはおかしなことではない。(Lyrical/poetic)
18b. 誰かと悲しみを共有することはおかしなことではない。(Normal)
It is not strange to share sadness with someone.
19. （あなたと）一緒に行きます。
I am going together (with you).
20. あの二人はいつも一緒です。
Those two are always together.
21. 私は父と電話で話しました。
I talked with my father on the telephone.
22. 彼氏と一緒に宿題をした。
I did homework together with my boyfriend.
23a. 同じ羽の鳥は一緒に集まる。
23b. 類は友を呼ぶ。
Birds of a feather flock together.
24. 一緒に来ませんか。
Won't you come with me?
25. 彼は恐怖と戦って、ついに勝った。
He fought against his fears, and he finally won.
26. 彼女と時々けんかする。
I sometimes argue with her.
27. 車とぶつかった。
I collided with a car.
28. 子供と遊ぶ。
To play with a child.
29. 彼と食事をともにした。
I had dinner with him.
30. 友達と会う。
To meet with a friend.
Grammar Note: と会う shows that both sides move (to see one another) while に会う shows that only one party moves, thus leading to meeting the person. Due to this discrepancy, for "to happen to meet someone/encounter someone," you can see X｛と・に｝ばったり（と）[会う・出会う].
Comparing
と may mark a subject being compared. As for 似る, ～に似る and ～と似る are possible but slightly different. と in this case marks one side of a mutual relation(ship) whereas に only shows the standard of comparison. They both, though, make the second person the basis of comparison when the pattern is XはY｛に・と｝似ている. Consider the following.
31a その父と子は似ている。〇
31b.その子はお父さんと似ている。 〇
31c. その子はお父さんに似ている。 〇
31d. その父は息子と似ている。 〇
31e. その父は息子に似ている。 X
The child resembles his father.
32a.この事件は以前とは異なる。
32b.以前の事件とは異なる。
32c. 以前の事件とは違う。
The case is different from before.
33. Xと比べる
To compare with X.
34. 彼と同じ考えです。
That is the same idea as his.
35. 人間と動物との違い
The difference between humans and animals.
Particle Note: The second instance of と here is not optional. The different と are different. The first is "and" and the second is "with" used here to show comparison, or in this case the opposite of comparison.
36. スペイン語と日本語はまったく似ていません。
The Spanish and Japanese don't resemble/match each other at all.
Particle Note: We've seen XはYと似ている and XはYに似ている, but XとYは似ている exists too. If the referents weren't mentioned, then you'd need something like お互いに for "each other", but you don't use the word every time you use 似ている.
Content of a Result
と and に are sometimes similar, but there is always a difference. と may show the result of something. It's used with verbs like 決める (to decide) and なる (to become). As for なる, になる and となる are possible. However, になる shows an end point of some change. Therefore, there is a duration to it. As for となる, it shows the content/substance of a result.
と shows a discrete change. This means that it shows the result of something not from a continuous process. と often sounds more stiff and formal. Another verb where there is this contrast is 改める (to reform; revise). This means that there are some phrases where と doesn't make a lot of sense.
37. いよいよ運動会の日となりました。
Field day has come at last.
38. 期末試験は二週間後と決まった。
It's been decided that the final test will be in 2 weeks.
39. 小雨となった。
It became a drizzle.
40a. 元気となる。△/X
40b. 元気になる。〇
To become better.
41. みぞれが雪となりました。
The sleet turned to snow.
漢字 Note: みぞれ is rarely written in 漢字 as 霙.