words

Know

The Oxford English Dictionary
Etymology: Cognate with Old High German -knāen...to recognize, to perceive, to comprehend, to understand; Old Icelandic kná (defective verb, first person singular; first person plural knegum ; past tense knátta ) to know how to do (something), to be able to < the same Indo-European base as classical Latin gnō- (preserved in archaic forms in early Latin authors and on inscriptions, while the prevalent form in classical Latin is nō- ; seen in the inceptive gnōscere to get to know, perfect gnōvī (used chiefly with present force, ‘to have got to know’, hence ‘to know’), past participle gnōtus ‘known’), ancient Greek γνω- (whence reduplicated and inceptive γιγνώσκειν to recognize, know, perceive, strong aorist ἔγνων ), Old Church Slavonic znati , Old Russian znati to know (Russian znat′ ), Old Prussian -sinnat (in ersinnat to realize, to acknowledge, posinnat to realize), Latvian zināt to know, Lithuanian žinoti to know, Sanskrit jñā- to know; ...

Of the many definitions offered, I liked this one best:

To recognize, acknowledge, perceive.

http://en.wiktionary.org/wiki/know

1. To be certain or sure about.
2. To be acquainted or familiar with; to have encountered.
3. To have knowledge of; to have memorised information, data, or facts about.
4. To understand (a subject).
5. To be informed about.
6. To experience.
7. To have sexual relations with.

dictionary.com

1. to perceive or understand as fact or truth; to apprehend clearly and with certainty: I know the situation fully.

2. to have established or fixed in the mind or memory: to know a poem by heart; Do you know the way to the park from here?

3. to be cognizant or aware of: I know it.

4.be acquainted with (a thing, place, person, etc.), as by sight, experience, or report: to know the mayor.

5.to understand from experience or attainment (usually followed by how  before an infinitive): to know how to make gingerbread.

Play

The Oxford English Dictionary
Etymology: Origin uncertain: perhaps cognate with Middle Dutch pleyen to dance, leap for joy, rejoice, be glad (compare also Dutch pleien to play a particular childrens' game), of uncertain etymology; a further connection has frequently been suggested with Old English plēon and related verbs in other Germanic languages, but this is very uncertain.

a smattering of definitions:

I. Senses relating to movement, exercise, and activity.

II. Of a living being: to move about swiftly, with a lively, irregular, or capricious motion; to spring, fly, or dart to and fro; to gambol, frisk; to flit, flutter. In later use spec. (Eng. regional): (of bees) to swarm; to fly about before swarming.

III. To get or bring oneself into something by fluttering or irregular movement. Obs. rare.

http://en.wiktionary.org/wiki/play

1. To act in a manner such that one has fun; to engage in activities expressly for the purpose of recreation.
2. To take part in amorous activity; to make love, fornicate; to have sex.  
3. To perform in a sport.
4. To participate in the game indicated.
5. To compete against, in a game
6. To act as the indicated role, especially in a performance.
7. To produce music using a musical instrument.

dictionary.com
1. to exercise or employ oneself in diversion, amusement, or recreation.
2. to do something in sport that is not to be taken seriously.
3. to amuse oneself; toy; trifle (often followed by with).
4. to take part or engage in a game.
5. to take part in a game for stakes; gamble.

Pattern

The Oxford English Dictionary
Etymology: Compare Middle French, French patronner to reproduce after a model (1392), to take as a model (used reflexive; 1437), to imitate (1611 in Cotgrave), to colour using a stencil (1676).

Definitions:
I. Senses relating to a model or example.
II. To design, sketch, plan
III. To exemplify, supply an example of

http://en.wiktionary.org/wiki/pattern

1. to apply a pattern
2. To make or design (anything) by, from, or after, something that serves as a pattern; to copy; to model; to imitate.  
3. to follow an example
4. To serve as an example for.

dictionary.com
1. to make or fashion after or according to a pattern.
2. to cover or mark with a pattern.
3. to imitate.
4. to attempt to match or duplicate.