21.20 IRS means the United States Internal Revenue Service.
21.21 Option means an award of an option to purchase Shares pursuant to Section 5.
21.22 Outside Director means a Director who is not an Employee of the Company or any Parent or Subsidiary and who is an independent director under the rules of The Nasdaq Stock Market, as may be amended from time to time.
21.23 Parent means any corporation (other than the Company) in an unbroken chain of corporations ending with the Company if each of such corporations other than the Company owns stock possessing fifty percent (50%) or more of the total combined voting power of all classes of stock in one of the other corporations in such chain.
21.24 Performance Factors means the factors selected by the Committee to determine whether performance goals established by the Committee applicable to Awards have been satisfied.
21.25 Performance Period means the period of service determined by the Committee during which years of service or performance is to be measured for the Award.
21.26 Permitted Transferee means any child, stepchild, grandchild, parent, stepparent, grandparent, spouse, former spouse, sibling, niece, nephew, mother-in-law, father-in-law, son-in-law, daughter-in-law, brother-in-law, or sister-in-law (including adoptive relationships) of the Employee, any person sharing the Employees household (other than a tenant or employee), a trust in which these persons (or the Employee) have more than 50% of the beneficial interest, a foundation in which these persons (or the Employee) control the management of assets, and any other entity in which these persons (or the Employee) own more than 50% of the voting interests.
21.27 Plan means this Sierra Oncology, Inc. 2018 Equity Inducement Plan.
21.28 Restricted Stock Unit means an Award granted pursuant to Section 6 of the Plan.
21.29 SEC means the United States Securities and Exchange Commission.
21.30 Securities Act means the United States Securities Act of 1933, as amended.
21.31 Service shall mean service as an Employee to the Company or a Parent, Subsidiary or Affiliate, subject to such further limitations as may be set forth in the Plan or the applicable Award Agreement. An Employee will not be deemed to have ceased to provide Service in the case of (a) sick leave, (b) military leave, or (c) any other leave of absence approved by the Company; provided, that such leave is for a period of not more than 90 days (x) unless reemployment upon the expiration of such leave is guaranteed by contract or statute, or (y) unless provided otherwise pursuant to formal policy adopted from time to time by the Company and issued and promulgated to employees in writing. In the case of any Employee on an approved leave of absence or a reduction in hours worked (for illustrative purposes only, a change in schedule from that of full-time to part-time), the Committee may make such provisions regarding suspension of or modification of vesting of the Award while on leave from the employ of the Company or a Parent, Subsidiary or Affiliate or during such change in working hours as it may deem appropriate, except that in no event may an Award be exercised after the expiration of the term set forth in the applicable Award Agreement. In the event of military leave, if required by applicable laws, vesting shall continue for the longest period that vesting continues under any other statutory or Company approved leave of absence and, upon a Employees returning from military leave (under conditions that would entitle him or her to protection upon such return under the Uniform Services Employment and Reemployment Rights